/*
 *  This file is part of RawTherapee.
 *
 *  Copyright (c) 2004-2010 Gabor Horvath <hgabor@rawtherapee.com>
 *
 *  RawTherapee is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  RawTherapee is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with RawTherapee.  If not, see <https://www.gnu.org/licenses/>.
 */
#include "histogrampanel.h"
#include "multilangmgr.h"
#include "guiutils.h"
#include "options.h"
#include <cstring>
#include <cmath>
#include "rtimage.h"
#include "rtscalable.h"
#include "rtengine/array2D.h"
#include "rtengine/color.h"
#include "rtengine/improcfun.h"
#include "rtengine/LUT.h"

using namespace rtengine;

constexpr float HistogramArea::MAX_BRIGHT;
constexpr float HistogramArea::MIN_BRIGHT;

using ScopeType = Options::ScopeType;

//
//
// HistogramPanel
HistogramPanel::HistogramPanel () :
    pointer_moved_delayed_call(
        [this](bool validPos, const rtengine::procparams::ColorManagementParams *cmp, int r, int g, int b)
        {
            bool update_hist_area = false, update_hist_rgb_area = false;

            if (!validPos) {
                // do something to un-show vertical bars
                if (histogramRGBArea) {
                    update_hist_rgb_area = histogramRGBArea->updatePointer(-1, -1, -1);
                }

                update_hist_area = histogramArea->updatePointer(-1, -1, -1);
            } else {
                // do something to show vertical bars
                if (histogramRGBArea) {
                    update_hist_rgb_area = histogramRGBArea->updatePointer(r, g, b, cmp);
                }

                update_hist_area = histogramArea->updatePointer(r, g, b, cmp);
            }

            if (histogramRGBArea && update_hist_rgb_area) {
                histogramRGBArea->queue_draw();
            }

            if (update_hist_area) {
                histogramArea->queue_draw();
            }
        },
        50,
        100
    ),
    panel_listener(nullptr)
{
    setExpandAlignProperties(this, true, true, Gtk::ALIGN_FILL, Gtk::ALIGN_FILL);
    set_name("HistogramPanel");

    histogramArea = Gtk::manage (new HistogramArea (this));
    setExpandAlignProperties(histogramArea, true, true, Gtk::ALIGN_FILL, Gtk::ALIGN_FILL);

    histogramRGBAreaHori.reset(new HistogramRGBAreaHori());
    setExpandAlignProperties(histogramRGBAreaHori.get(), true, false, Gtk::ALIGN_FILL, Gtk::ALIGN_END);

    histogramRGBAreaVert.reset(new HistogramRGBAreaVert());
    setExpandAlignProperties(histogramRGBAreaVert.get(), false, true, Gtk::ALIGN_END, Gtk::ALIGN_FILL);

    const auto& options = App::get().options();
    switch (options.histogramScopeType) {
        case ScopeType::NONE:
        case ScopeType::HISTOGRAM_RAW:
        case ScopeType::VECTORSCOPE_HC:
        case ScopeType::VECTORSCOPE_HS:
            histogramRGBArea = nullptr;
            break;
        case ScopeType::PARADE:
        case ScopeType::WAVEFORM:
            histogramRGBArea = histogramRGBAreaVert.get();
            break;
        case ScopeType::HISTOGRAM:
            histogramRGBArea = histogramRGBAreaHori.get();
            break;
    }

    // connecting the two childs
    histogramArea->signal_factor_changed().connect( sigc::mem_fun(*histogramRGBAreaHori, &HistogramRGBArea::factorChanged) );
    histogramArea->signal_factor_changed().connect( sigc::mem_fun(*histogramRGBAreaVert, &HistogramRGBArea::factorChanged) );

    gfxGrid = Gtk::manage (new Gtk::Grid ());
    gfxGrid->set_row_spacing(1);
    gfxGrid->set_column_spacing(1);
    gfxGrid->add(*histogramArea);
    gfxGrid->attach_next_to(
        *histogramRGBAreaVert, *histogramArea,
        options.histogramPosition == 1 ? Gtk::POS_RIGHT : Gtk::POS_LEFT,
        1,
        1
    );
    gfxGrid->attach_next_to(*histogramRGBAreaHori, *histogramArea, Gtk::POS_BOTTOM, 1, 1);
    histogramRGBAreaHori->set_no_show_all();
    histogramRGBAreaVert->set_no_show_all();

    redImage   = new RTImage ("histogram-red-on-small", Gtk::ICON_SIZE_BUTTON);
    greenImage = new RTImage ("histogram-green-on-small", Gtk::ICON_SIZE_BUTTON);
    blueImage  = new RTImage ("histogram-blue-on-small", Gtk::ICON_SIZE_BUTTON);
    valueImage = new RTImage ("histogram-silver-on-small", Gtk::ICON_SIZE_BUTTON);
    chroImage  = new RTImage ("histogram-gold-on-small", Gtk::ICON_SIZE_BUTTON);
    barImage   = new RTImage ("histogram-bar-on-small", Gtk::ICON_SIZE_BUTTON);

    redImage_g   = new RTImage ("histogram-red-off-small", Gtk::ICON_SIZE_BUTTON);
    greenImage_g = new RTImage ("histogram-green-off-small", Gtk::ICON_SIZE_BUTTON);
    blueImage_g  = new RTImage ("histogram-blue-off-small", Gtk::ICON_SIZE_BUTTON);
    valueImage_g = new RTImage ("histogram-silver-off-small", Gtk::ICON_SIZE_BUTTON);
    chroImage_g  = new RTImage ("histogram-gold-off-small", Gtk::ICON_SIZE_BUTTON);
    barImage_g   = new RTImage ("histogram-bar-off-small", Gtk::ICON_SIZE_BUTTON);

    mode0Image  = new RTImage ("histogram-mode-linear-small", Gtk::ICON_SIZE_BUTTON);
    mode1Image  = new RTImage ("histogram-mode-logx-small", Gtk::ICON_SIZE_BUTTON);
    mode2Image  = new RTImage ("histogram-mode-logxy-small", Gtk::ICON_SIZE_BUTTON);

    Gtk::Image* histImage = Gtk::manage(new RTImage("histogram-type-histogram-small", Gtk::ICON_SIZE_BUTTON));
    Gtk::Image* histRawImage = Gtk::manage(new RTImage("histogram-type-histogram-raw-small", Gtk::ICON_SIZE_BUTTON));
    Gtk::Image* paradeImage = Gtk::manage(new RTImage("histogram-type-parade-small", Gtk::ICON_SIZE_BUTTON));
    Gtk::Image* waveImage = Gtk::manage(new RTImage("histogram-type-waveform-small", Gtk::ICON_SIZE_BUTTON));
    Gtk::Image* vectHcImage = Gtk::manage(new RTImage("histogram-type-vectorscope-hc-small", Gtk::ICON_SIZE_BUTTON));
    Gtk::Image* vectHsImage = Gtk::manage(new RTImage("histogram-type-vectorscope-hs-small", Gtk::ICON_SIZE_BUTTON));

    showRed   = Gtk::manage (new Gtk::ToggleButton ());
    showGreen = Gtk::manage (new Gtk::ToggleButton ());
    showBlue  = Gtk::manage (new Gtk::ToggleButton ());
    showValue = Gtk::manage (new Gtk::ToggleButton ());
    showChro  = Gtk::manage (new Gtk::ToggleButton ());
    showMode  = Gtk::manage (new Gtk::Button ());
    showBAR   = Gtk::manage (new Gtk::ToggleButton ());
    scopeOptions = Gtk::manage (new Gtk::ToggleButton ());

    Gtk::RadioButtonGroup scopeTypeGroup;
    scopeHistBtn = Gtk::manage(new Gtk::RadioButton(scopeTypeGroup));
    scopeHistRawBtn = Gtk::manage(new Gtk::RadioButton(scopeTypeGroup));
    scopeParadeBtn = Gtk::manage(new Gtk::RadioButton(scopeTypeGroup));
    scopeWaveBtn = Gtk::manage(new Gtk::RadioButton(scopeTypeGroup));
    scopeVectHcBtn = Gtk::manage(new Gtk::RadioButton(scopeTypeGroup));
    scopeVectHsBtn = Gtk::manage(new Gtk::RadioButton(scopeTypeGroup));
    scopeHistBtn->set_mode(false);
    scopeHistRawBtn->set_mode(false);
    scopeParadeBtn->set_mode(false);
    scopeWaveBtn->set_mode(false);
    scopeVectHcBtn->set_mode(false);
    scopeVectHsBtn->set_mode(false);

    showRed->set_name("histButton");
    showRed->set_can_focus(false);
    showGreen->set_name("histButton");
    showGreen->set_can_focus(false);
    showBlue->set_name("histButton");
    showBlue->set_can_focus(false);
    showValue->set_name("histButton");
    showValue->set_can_focus(false);
    showChro->set_name("histButton");
    showChro->set_can_focus(false);
    showMode->set_name("histButton");
    showMode->set_can_focus(false);
    scopeOptions->set_name("histButton");
    scopeOptions->set_can_focus(false);
    showBAR->set_name("histButton");
    showBAR->set_can_focus(false);
    scopeHistBtn->set_name("histButton");
    scopeHistBtn->set_can_focus(false);
    scopeHistRawBtn->set_name("histButton");
    scopeHistRawBtn->set_can_focus(false);
    scopeParadeBtn->set_name("histButton");
    scopeParadeBtn->set_can_focus(false);
    scopeWaveBtn->set_name("histButton");
    scopeWaveBtn->set_can_focus(false);
    scopeVectHcBtn->set_name("histButton");
    scopeVectHcBtn->set_can_focus(false);
    scopeVectHsBtn->set_name("histButton");
    scopeVectHsBtn->set_can_focus(false);

    showRed->set_relief (Gtk::RELIEF_NONE);
    showGreen->set_relief (Gtk::RELIEF_NONE);
    showBlue->set_relief (Gtk::RELIEF_NONE);
    showValue->set_relief (Gtk::RELIEF_NONE);
    showChro->set_relief (Gtk::RELIEF_NONE);
    showMode->set_relief (Gtk::RELIEF_NONE);
    scopeOptions->set_relief (Gtk::RELIEF_NONE);
    showBAR->set_relief (Gtk::RELIEF_NONE);
    scopeHistBtn->set_relief (Gtk::RELIEF_NONE);
    scopeHistRawBtn->set_relief (Gtk::RELIEF_NONE);
    scopeParadeBtn->set_relief (Gtk::RELIEF_NONE);
    scopeWaveBtn->set_relief (Gtk::RELIEF_NONE);
    scopeVectHcBtn->set_relief (Gtk::RELIEF_NONE);
    scopeVectHsBtn->set_relief (Gtk::RELIEF_NONE);

    showRed->set_tooltip_text   (M("HISTOGRAM_TOOLTIP_R"));
    showGreen->set_tooltip_text (M("HISTOGRAM_TOOLTIP_G"));
    showBlue->set_tooltip_text  (M("HISTOGRAM_TOOLTIP_B"));
    showValue->set_tooltip_text (M("HISTOGRAM_TOOLTIP_L"));
    showChro->set_tooltip_text  (M("HISTOGRAM_TOOLTIP_CHRO"));
    showMode->set_tooltip_text  (M("HISTOGRAM_TOOLTIP_MODE"));
    scopeOptions->set_tooltip_text(M("HISTOGRAM_TOOLTIP_SHOW_OPTIONS"));
    scopeHistBtn->set_tooltip_text(M("HISTOGRAM_TOOLTIP_TYPE_HISTOGRAM"));
    scopeHistRawBtn->set_tooltip_text(M("HISTOGRAM_TOOLTIP_TYPE_HISTOGRAM_RAW"));
    scopeParadeBtn->set_tooltip_text(M("HISTOGRAM_TOOLTIP_TYPE_PARADE"));
    scopeWaveBtn->set_tooltip_text(M("HISTOGRAM_TOOLTIP_TYPE_WAVEFORM"));
    scopeVectHcBtn->set_tooltip_text(M("HISTOGRAM_TOOLTIP_TYPE_VECTORSCOPE_HC"));
    scopeVectHsBtn->set_tooltip_text(M("HISTOGRAM_TOOLTIP_TYPE_VECTORSCOPE_HS"));

    buttonGrid = Gtk::manage (new Gtk::Grid ());
    buttonGrid->set_orientation(Gtk::ORIENTATION_HORIZONTAL);
    persistentButtons = Gtk::manage(new Gtk::Box());
    persistentButtons->set_orientation(Gtk::ORIENTATION_VERTICAL);
    optionButtons = Gtk::manage(new Gtk::Box());
    optionButtons->set_orientation(Gtk::ORIENTATION_VERTICAL);

    showRed->set_active   (options.histogramRed);
    showGreen->set_active (options.histogramGreen);
    showBlue->set_active  (options.histogramBlue);
    showValue->set_active (options.histogramLuma);
    showChro->set_active  (options.histogramChroma);
    // no showMode->set_active(), as it's not a ToggleButton
    scopeOptions->set_active(options.histogramShowOptionButtons);
    showBAR->set_active   (options.histogramBar);

    showRed->set_image   (showRed->get_active()   ? *redImage   : *redImage_g);
    showGreen->set_image (showGreen->get_active() ? *greenImage : *greenImage_g);
    showBlue->set_image  (showBlue->get_active()  ? *blueImage  : *blueImage_g);
    showValue->set_image (showValue->get_active() ? *valueImage : *valueImage_g);
    showChro->set_image  (showChro->get_active()  ? *chroImage  : *chroImage_g);
    if (options.histogramDrawMode == 0)
        showMode->set_image(*mode0Image);
    else if (options.histogramDrawMode == 1)
        showMode->set_image(*mode1Image);
    else
        showMode->set_image(*mode2Image);
    scopeHistBtn->set_image(*histImage);
    scopeHistRawBtn->set_image(*histRawImage);
    scopeParadeBtn->set_image(*paradeImage);
    scopeWaveBtn->set_image(*waveImage);
    scopeVectHcBtn->set_image(*vectHcImage);
    scopeVectHsBtn->set_image(*vectHsImage);
    switch(options.histogramScopeType) {
        case ScopeType::HISTOGRAM:
            scopeHistBtn->set_active();
            break;
        case ScopeType::HISTOGRAM_RAW:
            scopeHistRawBtn->set_active();
            break;
        case ScopeType::PARADE:
            scopeParadeBtn->set_active();
            break;
        case ScopeType::WAVEFORM:
            scopeWaveBtn->set_active();
            break;
        case ScopeType::VECTORSCOPE_HS:
            scopeVectHsBtn->set_active();
            break;
        case ScopeType::VECTORSCOPE_HC:
            scopeVectHcBtn->set_active();
            break;
        case ScopeType::NONE:
            break;
    }
    scopeOptions->set_image(*Gtk::manage(new RTImage("histogram-ellipsis-small")));
    showBAR->set_image   (showBAR->get_active()   ? *barImage   : *barImage_g);

    setExpandAlignProperties(showRed, false, false, Gtk::ALIGN_CENTER, Gtk::ALIGN_CENTER);
    setExpandAlignProperties(showGreen, false, false, Gtk::ALIGN_CENTER, Gtk::ALIGN_CENTER);
    setExpandAlignProperties(showBlue, false, false, Gtk::ALIGN_CENTER, Gtk::ALIGN_CENTER);
    setExpandAlignProperties(showValue, false, false, Gtk::ALIGN_CENTER, Gtk::ALIGN_CENTER);
    setExpandAlignProperties(showChro, false, false, Gtk::ALIGN_CENTER, Gtk::ALIGN_CENTER);
    setExpandAlignProperties(showMode, false, false, Gtk::ALIGN_CENTER, Gtk::ALIGN_CENTER);
    setExpandAlignProperties(scopeOptions, false, false, Gtk::ALIGN_START, Gtk::ALIGN_CENTER);
    setExpandAlignProperties(showBAR, false, false, Gtk::ALIGN_CENTER, Gtk::ALIGN_CENTER);
    setExpandAlignProperties(scopeOptions, true, false, Gtk::ALIGN_FILL, Gtk::ALIGN_FILL);
    setExpandAlignProperties(scopeHistBtn, true, false, Gtk::ALIGN_FILL, Gtk::ALIGN_FILL);
    setExpandAlignProperties(scopeHistRawBtn, true, false, Gtk::ALIGN_FILL, Gtk::ALIGN_FILL);
    setExpandAlignProperties(scopeParadeBtn, true, false, Gtk::ALIGN_FILL, Gtk::ALIGN_FILL);
    setExpandAlignProperties(scopeWaveBtn, true, false, Gtk::ALIGN_FILL, Gtk::ALIGN_FILL);
    setExpandAlignProperties(scopeVectHcBtn, true, false, Gtk::ALIGN_FILL, Gtk::ALIGN_FILL);
    setExpandAlignProperties(scopeVectHsBtn, true, false, Gtk::ALIGN_FILL, Gtk::ALIGN_FILL);
    setExpandAlignProperties(persistentButtons, false, true, Gtk::ALIGN_START, Gtk::ALIGN_FILL);
    setExpandAlignProperties(optionButtons, false, true, Gtk::ALIGN_START, Gtk::ALIGN_FILL);

    showRed->signal_toggled().connect( sigc::mem_fun(*this, &HistogramPanel::red_toggled), showRed );
    showGreen->signal_toggled().connect( sigc::mem_fun(*this, &HistogramPanel::green_toggled), showGreen );
    showBlue->signal_toggled().connect( sigc::mem_fun(*this, &HistogramPanel::blue_toggled), showBlue );
    showValue->signal_toggled().connect( sigc::mem_fun(*this, &HistogramPanel::value_toggled), showValue );
    showChro->signal_toggled().connect( sigc::mem_fun(*this, &HistogramPanel::chro_toggled), showChro );
    showMode->signal_released().connect( sigc::mem_fun(*this, &HistogramPanel::mode_released), showMode );
    scopeOptions->signal_toggled().connect(sigc::mem_fun(*this, &HistogramPanel::scopeOptionsToggled));
    showBAR->signal_toggled().connect( sigc::mem_fun(*this, &HistogramPanel::bar_toggled), showBAR );
    scopeHistBtn->signal_toggled().connect(sigc::bind(sigc::mem_fun(*this, &HistogramPanel::type_selected), scopeHistBtn));
    scopeHistRawBtn->signal_toggled().connect(sigc::bind(sigc::mem_fun(*this, &HistogramPanel::type_selected), scopeHistRawBtn));
    scopeParadeBtn->signal_toggled().connect(sigc::bind(sigc::mem_fun(*this, &HistogramPanel::type_selected), scopeParadeBtn));
    scopeWaveBtn->signal_toggled().connect(sigc::bind(sigc::mem_fun(*this, &HistogramPanel::type_selected), scopeWaveBtn));
    scopeVectHcBtn->signal_toggled().connect(sigc::bind(sigc::mem_fun(*this, &HistogramPanel::type_selected), scopeVectHcBtn));
    scopeVectHsBtn->signal_toggled().connect(sigc::bind(sigc::mem_fun(*this, &HistogramPanel::type_selected), scopeVectHsBtn));

    brightnessWidget = Gtk::manage(new Gtk::Scale(Gtk::ORIENTATION_VERTICAL));
    brightnessWidget->set_inverted();
    brightnessWidget->set_range(log(HistogramArea::MIN_BRIGHT), log(HistogramArea::MAX_BRIGHT));
    brightnessWidget->set_draw_value(false);
    brightnessWidget->signal_value_changed().connect(sigc::mem_fun(*this, &HistogramPanel::brightnessWidgetValueChanged));
    brightnessWidget->set_name("histScale");
    brightnessWidget->set_tooltip_text(M("HISTOGRAM_TOOLTIP_TRACE_BRIGHTNESS"));
    setExpandAlignProperties(brightnessWidget, true, false, Gtk::ALIGN_CENTER, Gtk::ALIGN_START);

    optionButtons->add(*showRed);
    optionButtons->add(*showGreen);
    optionButtons->add(*showBlue);
    optionButtons->add(*showValue);
    optionButtons->add(*showChro);
    optionButtons->add(*showMode);
    optionButtons->add(*showBAR);
    optionButtons->add(*brightnessWidget);

    Gtk::Separator* separator = Gtk::manage(new Gtk::Separator(Gtk::ORIENTATION_VERTICAL));
    setExpandAlignProperties(separator, true, false, Gtk::ALIGN_FILL, Gtk::ALIGN_CENTER);
    persistentButtons->add(*scopeHistBtn);
    persistentButtons->add(*scopeHistRawBtn);
    persistentButtons->add(*scopeParadeBtn);
    persistentButtons->add(*scopeWaveBtn);
    persistentButtons->add(*scopeVectHsBtn);
    persistentButtons->add(*scopeVectHcBtn);
    persistentButtons->add(*separator);
    persistentButtons->add(*scopeOptions);

    // Put the button vbox next to the window's border to be less disturbing
    if (options.histogramPosition == 1) {
        buttonGrid->add(*persistentButtons);
        buttonGrid->add(*optionButtons);

        add (*buttonGrid);
        add (*gfxGrid);
    } else {
        buttonGrid->add(*optionButtons);
        buttonGrid->add(*persistentButtons);

        add (*gfxGrid);
        add (*buttonGrid);
    }

    show_all ();
    optionButtons->set_no_show_all();
    optionButtons->set_visible(options.histogramShowOptionButtons);

    type_changed();

    // Update histogramArea internal parameters from options
    histogramArea->updateFromOptions();

    if (histogramRGBArea) {
        // Update histogramRGBArea internal parameters from options
        histogramRGBArea->updateFromOptions();
    }

    brightness_changed_connection = histogramArea->getBrighnessChangedSignal().connect(sigc::mem_fun(*this, &HistogramPanel::brightnessUpdated));
    rconn = signal_size_allocate().connect( sigc::mem_fun(*this, &HistogramPanel::resized) );

    histogramArea->setBrightness(options.histogramTraceBrightness);
}

HistogramPanel::~HistogramPanel ()
{
    pointer_moved_delayed_call.cancel();

    delete redImage;
    delete greenImage;
    delete blueImage;
    delete valueImage;
    delete chroImage;
    delete mode0Image;
    delete mode1Image;
    delete mode2Image;
    delete barImage;

    delete redImage_g;
    delete greenImage_g;
    delete blueImage_g;
    delete valueImage_g;
    delete chroImage_g;
    delete barImage_g;
}

void HistogramPanel::showRGBBar()
{
    histogramRGBAreaHori->set_visible(
        histogramRGBArea == histogramRGBAreaHori.get() && showBAR->get_active());
    histogramRGBAreaVert->set_visible(
        histogramRGBArea == histogramRGBAreaVert.get() && showBAR->get_active());
}

void HistogramPanel::resized (Gtk::Allocation& req)
{
    static int old_height = 0;
    static int old_width = 0;

    bool size_changed =
        old_height != req.get_height() || old_width != req.get_width();

    // Set HistogramArea invalid
    if (size_changed) {
        histogramArea->updatePointer(-1, -1, -1);
        histogramArea->queue_draw ();
    }

    // Set HistogramRGBArea invalid
    if (histogramRGBArea && size_changed) {
        histogramRGBArea->updatePointer(-1, -1, -1);
        histogramRGBArea->queue_draw ();
    }

    // Store current height of the histogram
    App::get().mut_options().histogramHeight = get_height();

    old_height = req.get_height();
    old_width = req.get_width();
}

void HistogramPanel::red_toggled ()
{
    // Update button image
    showRed->set_image(showRed->get_active() ? *redImage : *redImage_g);
    // Update options value
    App::get().mut_options().histogramRed = showRed->get_active() ? true : false;
    // Update drawing areas
    rgbv_toggled();
}

void HistogramPanel::green_toggled ()
{
    // Update button image
    showGreen->set_image(showGreen->get_active() ? *greenImage : *greenImage_g);
    // Update options value
    App::get().mut_options().histogramGreen = showGreen->get_active() ? true : false;
    // Update drawing areas
    rgbv_toggled();
}

void HistogramPanel::blue_toggled ()
{
    // Update button image
    showBlue->set_image(showBlue->get_active() ? *blueImage : *blueImage_g);
    // Update options value
    App::get().mut_options().histogramBlue = showBlue->get_active() ? true : false;
    // Update drawing areas
    rgbv_toggled();
}
void HistogramPanel::value_toggled ()
{
    // Update button image
    showValue->set_image(showValue->get_active() ? *valueImage : *valueImage_g);
    // Update options value
    App::get().mut_options().histogramLuma = showValue->get_active() ? true : false;
    // Update drawing areas
    rgbv_toggled();
}
void HistogramPanel::chro_toggled ()
{
    // Update button image
    showChro->set_image(showChro->get_active() ? *chroImage : *chroImage_g);
    // Update options value
    App::get().mut_options().histogramChroma = showChro->get_active() ? true : false;
    // Update drawing areas
    rgbv_toggled();
}

void HistogramPanel::mode_released ()
{
    auto& options = App::get().mut_options();
    // Update options value
    options.histogramDrawMode = (options.histogramDrawMode + 1) % 3;
    // Update button image
    if (options.histogramDrawMode == 0) {
        showMode->set_image(*mode0Image);
    } else if (options.histogramDrawMode == 1) {
        showMode->set_image(*mode1Image);
    } else {
        showMode->set_image(*mode2Image);
    }
    // Update drawing areas
    rgbv_toggled();
}

void HistogramPanel::brightnessWidgetValueChanged(void)
{
    ConnectionBlocker blocker(brightness_changed_connection);
    histogramArea->setBrightness(exp(brightnessWidget->get_value()));
    App::get().mut_options().histogramTraceBrightness = histogramArea->getBrightness();
}

void HistogramPanel::brightnessUpdated(float brightness)
{
    brightnessWidget->set_value(log(brightness));
    App::get().mut_options().histogramTraceBrightness = histogramArea->getBrightness();
}

void HistogramPanel::scopeOptionsToggled()
{
    // Update options value
    App::get().mut_options().histogramShowOptionButtons = scopeOptions->get_active();
    // Show/hide secondary buttons column
    optionButtons->set_visible(scopeOptions->get_active());
}

void HistogramPanel::type_selected(Gtk::RadioButton* button)
{
    // Get radio button value
    ScopeType new_type = ScopeType::NONE;

    if (button == scopeHistBtn) {
        new_type = ScopeType::HISTOGRAM;
    } else if (button == scopeHistRawBtn) {
        new_type = ScopeType::HISTOGRAM_RAW;
    } else if (button == scopeParadeBtn) {
        new_type = ScopeType::PARADE;
    } else if (button == scopeWaveBtn) {
        new_type = ScopeType::WAVEFORM;
    } else if (button == scopeVectHcBtn) {
        new_type = ScopeType::VECTORSCOPE_HC;
    } else if (button == scopeVectHsBtn) {
        new_type = ScopeType::VECTORSCOPE_HS;
    }

    auto& options = App::get().mut_options();
    // Do not update if selected radio button is identical
    if (new_type == options.histogramScopeType) {
        return;
    }

    // Update options value
    options.histogramScopeType = new_type;
    // Update histogram panel GUI based on scope type
    type_changed();

    if (histogramRGBArea) {
        // Update histogramRGBArea internal parameters from options
        histogramRGBArea->updateFromOptions();
        // Set pointer invalid for histogramRGBArea
        histogramRGBArea->updatePointer(-1, -1, -1);
        // Update drawing area
        histogramRGBArea->queue_draw ();
    }

    // Update histogramArea internal parameters from options
    histogramArea->updateFromOptions();
    // Set pointer invalid for histogramArea
    histogramArea->updatePointer(-1, -1, -1);
    // Update drawing area
    // Note: No need to call queue_draw as an update of histogram data
    // is requested in the type_changed function: queue_draw call will
    // be performed in update function when updated histogram data are
    // provided
    // histogramArea->queue_draw();
}

void HistogramPanel::type_changed()
{
    const auto& options = App::get().options();
    switch (options.histogramScopeType) {
        case ScopeType::HISTOGRAM:
            showRed->show();
            showGreen->show();
            showBlue->show();
            showValue->show();
            showChro->show();
            showMode->show();
            showBAR->show();
            showBAR->set_tooltip_text(M("HISTOGRAM_TOOLTIP_BAR"));
            brightnessWidget->hide();
            histogramRGBArea = histogramRGBAreaHori.get();
            break;
        case ScopeType::HISTOGRAM_RAW:
            showRed->show();
            showGreen->show();
            showBlue->show();
            showValue->hide();
            showChro->hide();
            showMode->show();
            showBAR->hide();
            brightnessWidget->hide();
            histogramRGBArea = nullptr;
            break;
        case ScopeType::PARADE:
        case ScopeType::WAVEFORM:
            showRed->show();
            showGreen->show();
            showBlue->show();
            showValue->show();
            showChro->hide();
            showMode->hide();
            showBAR->show();
            showBAR->set_tooltip_text(M("HISTOGRAM_TOOLTIP_BAR"));
            brightnessWidget->show();
            histogramRGBArea = histogramRGBAreaVert.get();
            break;
        case ScopeType::VECTORSCOPE_HC:
        case ScopeType::VECTORSCOPE_HS:
            showRed->hide();
            showGreen->hide();
            showBlue->hide();
            showValue->hide();
            showChro->hide();
            showMode->hide();
            showBAR->show();
            showBAR->set_tooltip_text(M("HISTOGRAM_TOOLTIP_CROSSHAIR"));
            brightnessWidget->show();
            histogramRGBArea = nullptr;
            break;
        case ScopeType::NONE:
            break;
    }

    // Request histogram data update
    if (panel_listener) {
        panel_listener->scopeTypeChanged(options.histogramScopeType);
    }

    // Update histogram bar visibility
    showRGBBar();
}

void HistogramPanel::bar_toggled ()
{
    // Update button image
    showBAR->set_image(showBAR->get_active() ? *barImage : *barImage_g);
    // Update options value
    App::get().mut_options().histogramBar = showBAR->get_active() ? true : false;
    // Update drawing areas
    rgbv_toggled();
    // Update histogram bar visibility
    showRGBBar();
}

void HistogramPanel::rgbv_toggled ()
{
    // Update Display
    // Update histogramArea internal parameters from options
    histogramArea->updateFromOptions();
    // Set pointer invalid for histogramArea
    histogramArea->updatePointer(-1, -1, -1);
    // Update drawing area
    histogramArea->queue_draw ();

    if (histogramRGBArea) {
        // Update histogramRGBArea internal parameters from options
        histogramRGBArea->updateFromOptions();
        // Set pointer invalid for histogramRGBArea
        histogramRGBArea->updatePointer(-1, -1, -1);
        // Update drawing area
        histogramRGBArea->queue_draw ();
    }
}

void HistogramPanel::pointerMoved (bool validPos, const rtengine::procparams::ColorManagementParams &cmp, int x, int y, int r, int g, int b, bool isRaw)
{
    pointer_moved_delayed_call(validPos, &cmp, r, g, b);
}

/*
 * Move the vertical button bar to the right side
 * only allowed values for align are Gtk::POS_LEFT and Gtk::POS_RIGHT
 */
void HistogramPanel::reorder (Gtk::PositionType align)
{
    if (align == Gtk::POS_LEFT) {
        gfxGrid->reference();
        removeIfThere(this, gfxGrid, false);
        add (*gfxGrid);
        gfxGrid->unreference();

        gfxGrid->remove(*histogramRGBAreaVert);
        gfxGrid->add(*histogramRGBAreaVert);

        optionButtons->reference();
        removeIfThere(buttonGrid, optionButtons, false);
        buttonGrid->add(*optionButtons);
        optionButtons->unreference();
    } else {
        buttonGrid->reference();
        removeIfThere(this, buttonGrid, false);
        add (*buttonGrid);
        buttonGrid->unreference();

        gfxGrid->remove(*histogramRGBAreaVert);
        gfxGrid->attach_next_to(*histogramRGBAreaVert, *histogramArea, Gtk::POS_LEFT, 1, 1);

        persistentButtons->reference();
        removeIfThere(buttonGrid, persistentButtons, false);
        buttonGrid->add(*persistentButtons);
        persistentButtons->unreference();
    }
}

// DrawModeListener interface:
void HistogramPanel::toggleButtonMode ()
{
    const auto& options = App::get().options();
    if (options.histogramDrawMode == 0)
        showMode->set_image(*mode0Image);
    else if (options.histogramDrawMode == 1)
        showMode->set_image(*mode1Image);
    else
        showMode->set_image(*mode2Image);
}

void HistogramPanel::setPanelListener(HistogramPanelListener* listener)
{
    panel_listener = listener;

    if (listener) {
        listener->scopeTypeChanged(App::get().options().histogramScopeType);
    }
}

//
//
//
// HistogramScaling
double HistogramScaling::log(double vsize, double val)
{
    //double factor = 10.0; // can be tuned if necessary - higher is flatter curve
    return vsize * std::log(factor / (factor + val)) / std::log(factor / (factor + vsize));
}

//
//
//
// HistogramRGBArea
HistogramRGBArea::HistogramRGBArea () :
    // Saved pointer parameters
    r(-1), g(-1), b(-1), lab_L(0.f), lab_a(0.f), lab_b(0.f), pointerValid(false),
    // Drawing options (initialized at options file values)
    needRed(App::get().options().histogramRed), needGreen(App::get().options().histogramGreen),
    needBlue(App::get().options().histogramBlue), needLuma(App::get().options().histogramLuma),
    needChroma(App::get().options().histogramChroma), scopeType(App::get().options().histogramScopeType),
    scaleMode(App::get().options().histogramDrawMode), showBar(App::get().options().histogramBar)
{
    get_style_context()->add_class("drawingarea");
    set_name("HistogramRGBArea");
}

HistogramRGBArea::~HistogramRGBArea () {}

void HistogramRGBArea::getPreferredThickness(int& min_thickness, int& natural_thickness) const
{
    int minimumLength = 0;
    int naturalLength = 0;
    getPreferredLength(minimumLength, naturalLength);
    getPreferredThicknessForLength(minimumLength, min_thickness, natural_thickness);
}

void HistogramRGBArea::getPreferredLength(int& min_length, int& natural_length) const
{
    min_length = RTScalable::scalePixelSize(60);
    natural_length = RTScalable::scalePixelSize(200);
}

void HistogramRGBArea::getPreferredThicknessForLength(int length, int& min_thickness, int& natural_thickness) const
{
    int bThickness = length / 30;

    if (bThickness > RTScalable::scalePixelSize(10)) {
        bThickness = RTScalable::scalePixelSize(10);
    } else if (bThickness < RTScalable::scalePixelSize(5)) {
        bThickness = RTScalable::scalePixelSize(5);
    }

    min_thickness = bThickness;
    natural_thickness = bThickness;
}

// unused?
void HistogramRGBArea::getPreferredLengthForThickness(int thickness, int& min_length, int& natural_length) const
{
    getPreferredLength(min_length, natural_length);
}

void HistogramRGBArea::updateDrawingArea (const ::Cairo::RefPtr< Cairo::Context> &cc)
{
    // Do not update drawing area if widget is not realized
    if (!get_realized ()) {
        return;
    }

    // Do not update drawing area if bar is not visible
    // (by user choice or according to scope type)
    if (!showBar || scopeType == Options::ScopeType::HISTOGRAM_RAW ||
            scopeType == Options::ScopeType::VECTORSCOPE_HC ||
            scopeType == Options::ScopeType::VECTORSCOPE_HS) {
        return;
    }

    // Do not update drawing area if pointer is not valid
    if (!pointerValid) {
        return;
    }

    // Note: updateDrawingArea is called by the on_draw function so its call does not need to be protected
    // GThreadLock lock; // All GUI access from idle_add callbacks or separate thread HAVE to be protected

    Glib::RefPtr<Gdk::Window> window = get_window();
    int winx, winy, winw, winh;
    window->get_geometry(winx, winy, winw, winh);

    cc->set_operator (Cairo::OPERATOR_OVER);
    cc->set_antialias(Cairo::ANTIALIAS_NONE);
    cc->set_line_width (1.0);

    if (needRed) {
        // Red
        cc->set_source_rgb(1.0, 0.0, 0.0);
        drawBar(cc, r, 255.0, winw, winh);
    }

    if (needGreen) {
        // Green
        cc->set_source_rgb(0.0, 1.0, 0.0);
        drawBar(cc, g, 255.0, winw, winh);
    }

    if (needBlue) {
        // Blue
        cc->set_source_rgb(0.0, 0.4, 1.0);
        drawBar(cc, b, 255.0, winw, winh);
    }

    if ((needLuma || needChroma)
            && (scopeType == Options::ScopeType::HISTOGRAM
                    || scopeType == Options::ScopeType::PARADE
                    || scopeType == Options::ScopeType::WAVEFORM)) {
        if (needLuma) {
            // Luma
            cc->set_source_rgb(1.0, 1.0, 1.0);
            drawBar(cc, lab_L, 32768., winw, winh);
        }

        if (needChroma && scopeType == Options::ScopeType::HISTOGRAM) {
            // Chroma
            double chromaval = sqrt(lab_a * lab_a + lab_b * lab_b) / (255. * 188);
            cc->set_source_rgb(0.9, 0.9, 0.0);
            drawBar(cc, chromaval, 1.0, winw, winh);
        }
    }
}

bool HistogramRGBArea::updatePointer (const int new_r, const int new_g, const int new_b, const rtengine::procparams::ColorManagementParams *cmp)
{
    // Do not update pointer values if bar is not visible
    // (by user choice or according to scope type)
    if (!showBar || scopeType == Options::ScopeType::HISTOGRAM_RAW ||
            scopeType == Options::ScopeType::VECTORSCOPE_HC ||
            scopeType == Options::ScopeType::VECTORSCOPE_HS) {
        return false;
    }

    // Do not update pointer values if values are identical
    if (r == new_r && g == new_g && b == new_b) {
        return false;
    }

    // Set pointer parameters to invalid if r = g = b = -1
    if (new_r == -1 || new_g == -1 || new_b == -1) {
        r = b = g = -1;
        lab_L = lab_a = lab_b = 0.;
        pointerValid = false;
    } else {
        r = new_r;
        g = new_g;
        b = new_b;
        ImProcFunctions::rgb2lab(
            static_cast<std::uint8_t>(r),
            static_cast<std::uint8_t>(g),
            static_cast<std::uint8_t>(b),
            lab_L, lab_a, lab_b,
            cmp != nullptr ? *cmp : App::get().fallbackColorCmp(),
            true);
        pointerValid = true;
    }

    return true;
}

void HistogramRGBArea::updateFromOptions ()
{
    const auto& options = App::get().options();
    needRed = options.histogramRed;
    needGreen = options.histogramGreen;
    needBlue = options.histogramBlue;
    needLuma = options.histogramLuma;
    needChroma = options.histogramChroma;
    scopeType = options.histogramScopeType;
    scaleMode = options.histogramDrawMode;
    showBar = options.histogramBar;
}

void HistogramRGBArea::on_realize ()
{
    Gtk::DrawingArea::on_realize();
    add_events(Gdk::BUTTON_PRESS_MASK);
}

bool HistogramRGBArea::on_draw(const ::Cairo::RefPtr< Cairo::Context> &cr)
{
    const Glib::RefPtr<Gtk::StyleContext> style = get_style_context();
    style->render_background(cr, 0., 0., static_cast<double>(get_width()), static_cast<double>(get_height()));

    // Draw drawing area
    // Note: As drawing area surface is updated inside on_draw function, hidpi is automatically supported
    updateDrawingArea(cr);

    style->render_frame (cr, 0., 0., static_cast<double>(get_width()), static_cast<double>(get_height()));

    return true;
}

bool HistogramRGBArea::on_button_press_event (GdkEventButton* event)
{

    if (event->type == GDK_2BUTTON_PRESS && event->button == 1) {
        // do something?
    }

    return true;
}

void HistogramRGBArea::factorChanged (double newFactor)
{
    factor = newFactor;
    // Request bar redraw (according to scope type)
    if (scopeType == Options::ScopeType::HISTOGRAM) {
        queue_draw();
    }
}

void HistogramRGBAreaHori::drawBar(const Cairo::RefPtr<Cairo::Context> &cc, const double value, const double max_value, const int winw, const int winh)
{
    double pos;
    if (App::get().options().histogramDrawMode < 2) {
        pos = padding + value * (winw - padding * 2.0) / max_value;
    } else {
        pos = padding + HistogramScaling::log (max_value, value) * (winw - padding * 2.0) / max_value;
    }
    cc->move_to(pos, 0.0);
    cc->line_to(pos, static_cast<double>(winh));
    cc->stroke();
}

Gtk::SizeRequestMode HistogramRGBAreaHori::get_request_mode_vfunc () const
{
    return Gtk::SIZE_REQUEST_HEIGHT_FOR_WIDTH;
}

void HistogramRGBAreaHori::get_preferred_height_vfunc (int &minimum_height, int &natural_height) const
{
    getPreferredThickness(minimum_height, natural_height);
}

void HistogramRGBAreaHori::get_preferred_width_vfunc (int &minimum_width, int &natural_width) const
{
    getPreferredLength(minimum_width, natural_width);
}

void HistogramRGBAreaHori::get_preferred_height_for_width_vfunc (int width, int &minimum_height, int &natural_height) const
{
    getPreferredThicknessForLength(width, minimum_height, natural_height);
}

void HistogramRGBAreaHori::get_preferred_width_for_height_vfunc (int height, int &minimum_width, int &natural_width) const
{
    getPreferredLengthForThickness(height, minimum_width, natural_width);
}

void HistogramRGBAreaVert::drawBar(const Cairo::RefPtr<Cairo::Context> &cc, const double value, const double max_value, const int winw, const int winh)
{
    double pos;
    const auto& options = App::get().options();
    if (options.histogramDrawMode < 2 || options.histogramScopeType == ScopeType::PARADE || options.histogramScopeType == ScopeType::WAVEFORM) {
        pos = padding + value * (winh - padding * 2.0 - 1) / max_value + 0.5;
    } else {
        pos = padding + HistogramScaling::log (max_value, value) * (winh - padding * 2.0) / max_value + 0.5;
    }
    cc->move_to(0.0, winh - pos);
    cc->line_to(winw, winh - pos);
    cc->stroke();
}

Gtk::SizeRequestMode HistogramRGBAreaVert::get_request_mode_vfunc () const
{
    return Gtk::SIZE_REQUEST_WIDTH_FOR_HEIGHT;
}

void HistogramRGBAreaVert::get_preferred_height_vfunc (int &minimum_height, int &natural_height) const
{
    getPreferredLength(minimum_height, natural_height);
}

void HistogramRGBAreaVert::get_preferred_width_vfunc (int &minimum_width, int &natural_width) const
{
    minimum_width = RTScalable::scalePixelSize(10);
    natural_width = minimum_width;
}

void HistogramRGBAreaVert::get_preferred_height_for_width_vfunc (int width, int &minimum_height, int &natural_height) const
{
    getPreferredLengthForThickness(width, minimum_height, natural_height);
}

void HistogramRGBAreaVert::get_preferred_width_for_height_vfunc (int height, int &minimum_width, int &natural_width) const
{
    get_preferred_width_vfunc(minimum_width, natural_width);
}

//
//
//
// HistogramArea
HistogramArea::HistogramArea (DrawModeListener *fml) :
    // Histogram parameters
    vectorscope_scale(0),
    vect_hc(0, 0), vect_hs(0, 0),
    vect_hc_buffer_dirty(true), vect_hs_buffer_dirty(true),
    waveform_scale(0),
    rwave(0, 0), gwave(0, 0),bwave(0, 0), lwave(0, 0),
    parade_buffer_r_dirty(true), parade_buffer_g_dirty(true), parade_buffer_b_dirty(true),
    wave_buffer_dirty(true), wave_buffer_luma_dirty(true),
    LUT_valid(false),
    // Intensity of waveform and vectorscope trace
    trace_brightness(1.f),
    // Saved pointer parameters
    pointer_red(-1), pointer_green(-1), pointer_blue(-1),
    pointer_a(0.f), pointer_b(0.f),
    pointer_valid(false),
    // Drawing options
    needRed(App::get().options().histogramRed),
    needGreen(App::get().options().histogramGreen),
    needBlue(App::get().options().histogramBlue),
    needLuma(App::get().options().histogramLuma),
    needChroma(App::get().options().histogramChroma),
    needPointer(App::get().options().histogramBar),
    scopeType(App::get().options().histogramScopeType),
    drawMode(App::get().options().histogramDrawMode), myDrawModeListener(fml),
    // Motion event management
    isPressed(false), movingPosition(0.0)
{
    rhist(256);
    ghist(256);
    bhist(256);
    lhist(256);
    chist(256);

    get_style_context()->add_class("drawingarea");
    set_name("HistogramArea");
}

HistogramArea::~HistogramArea ()
{
    idle_register.destroy();
}

Gtk::SizeRequestMode HistogramArea::get_request_mode_vfunc () const
{
    return Gtk::SIZE_REQUEST_CONSTANT_SIZE;
}

void HistogramArea::get_preferred_height_vfunc (int &minimum_height, int &natural_height) const
{
    minimum_height = RTScalable::scalePixelSize(100);
    natural_height = RTScalable::scalePixelSize(200);
}

void HistogramArea::get_preferred_width_vfunc (int &minimum_width, int &natural_width) const
{
    minimum_width = RTScalable::scalePixelSize(200);
    natural_width = RTScalable::scalePixelSize(400);
}

void HistogramArea::get_preferred_height_for_width_vfunc (int width, int &minimum_height, int &natural_height) const
{
    minimum_height = 0;
    natural_height = 0;
}

void HistogramArea::get_preferred_width_for_height_vfunc (int height, int &minimum_width, int &natural_width) const
{
    get_preferred_width_vfunc (minimum_width, natural_width);
}

void HistogramArea::updateFromOptions ()
{
    const auto& options = App::get().options();
    wave_buffer_dirty = wave_buffer_dirty || needRed != options.histogramRed ||
            needGreen != options.histogramGreen || needBlue != options.histogramBlue;

    needRed = options.histogramRed;
    needGreen = options.histogramGreen;
    needBlue = options.histogramBlue;
    needLuma = options.histogramLuma;
    needChroma = options.histogramChroma;
    drawMode = options.histogramDrawMode;
    scopeType = options.histogramScopeType;
    needPointer = options.histogramBar;
}

void HistogramArea::update(
    const LUTu& histRed,
    const LUTu& histGreen,
    const LUTu& histBlue,
    const LUTu& histLuma,
    const LUTu& histChroma,
    const LUTu& histRedRaw,
    const LUTu& histGreenRaw,
    const LUTu& histBlueRaw,
    int vectorscopeScale,
    const array2D<int>& vectorscopeHC,
    const array2D<int>& vectorscopeHS,
    int waveformScale,
    const array2D<int>& waveformRed,
    const array2D<int>& waveformGreen,
    const array2D<int>& waveformBlue,
    const array2D<int>& waveformLuma
)
{
    // Note: This function is called outside of GUI threads
    idle_register.add(
        [this, &histRed, &histGreen, &histBlue, &histLuma, &histChroma, &histRedRaw,
                &histGreenRaw, &histBlueRaw, vectorscopeScale, &vectorscopeHC,
                &vectorscopeHS, waveformScale, &waveformRed, &waveformGreen,
                &waveformBlue, &waveformLuma]() -> bool {
        GThreadLock lock; // All GUI access from idle_add callbacks or separate thread HAVE to be protected

        if (histRed) {
            switch (scopeType) {
                case ScopeType::HISTOGRAM:
                    rhist = histRed;
                    ghist = histGreen;
                    bhist = histBlue;
                    lhist = histLuma;
                    chist = histChroma;
                    break;
                case ScopeType::HISTOGRAM_RAW:
                    // Raw histogram data are always provided (refer below)
                    break;
                case ScopeType::PARADE:
                case ScopeType::WAVEFORM: {
                    MYWRITERLOCK(wave_lock, wave_mutex)
                    waveform_scale = waveformScale;
                    rwave = waveformRed;
                    gwave = waveformGreen;
                    bwave = waveformBlue;
                    lwave = waveformLuma;
                    parade_buffer_r_dirty = parade_buffer_g_dirty = parade_buffer_b_dirty = wave_buffer_dirty = wave_buffer_luma_dirty = true;
                    break;
                }
                case ScopeType::VECTORSCOPE_HS:
                    vectorscope_scale = vectorscopeScale;
                    vect_hs = vectorscopeHS;
                    vect_hs_buffer_dirty = true;
                    break;
                case ScopeType::VECTORSCOPE_HC:
                    vectorscope_scale = vectorscopeScale;
                    vect_hc = vectorscopeHC;
                    vect_hc_buffer_dirty = true;
                    break;
                case ScopeType::NONE:
                    break;
            }
            // Raw histogram data are always provided
            rhistRaw = histRedRaw;
            ghistRaw = histGreenRaw;
            bhistRaw = histBlueRaw;

            LUT_valid = true;
        } else {
            LUT_valid = false;
        }

        // Request GUI redraw
        queue_draw();

        return false;
        }
    );
}

void HistogramArea::updateDrawingArea (const ::Cairo::RefPtr< Cairo::Context> &cr)
{
    // Do not update drawing area if widget is not realized
    if (!get_realized ()) {
        return;
    }

    // Note: updateDrawingArea is called by the on_draw function so its call does not need to be protected
    // GThreadLock lock; // All GUI access from idle_add callbacks or separate thread HAVE to be protected

    Glib::RefPtr<Gdk::Window> window = get_window();
    int winx, winy, winw, winh;
    window->get_geometry(winx, winy, winw, winh);

    // Setup drawing
    cr->set_operator (Cairo::OPERATOR_OVER);

    // Prepare drawing gridlines first
    cr->set_source_rgba (1., 1., 1., 0.25);
    cr->set_line_width (1.0);
    cr->set_antialias(Cairo::ANTIALIAS_NONE);
    cr->set_line_join(Cairo::LINE_JOIN_MITER);
    cr->set_line_cap(Cairo::LINE_CAP_BUTT);
    const std::valarray<double> ch_ds = {4.};
    cr->set_dash (ch_ds, 0);

    // determine the number of h-gridlines based on current h
    int nrOfHGridPartitions = static_cast<int>(rtengine::min (16.0, pow (2.0, floor ((winh - 100) / 250) + 2)));
    int nrOfVGridPartitions = 8; // always show 8 stops (lines at 1,3,7,15,31,63,127)

    // draw vertical gridlines
    if (scopeType == Options::ScopeType::HISTOGRAM || scopeType == Options::ScopeType::HISTOGRAM_RAW) {
        for (int i = 0; i <= nrOfVGridPartitions; i++) {
            double xpos = padding + 0.5;
            if (drawMode < 2) {
                xpos += (pow(2.0,i) - 1) * (winw - padding * 2.0) / 255.0;
            } else {
                xpos += HistogramScaling::log (255, pow(2.0,i) - 1) * (winw - padding * 2.0) / 255.0;
            }
            cr->move_to (xpos, 0.);
            cr->line_to (xpos, winh);
            cr->stroke ();
        }
    }

    // draw horizontal gridlines
    if (scopeType == Options::ScopeType::PARADE || scopeType == Options::ScopeType::WAVEFORM) {
        for (int i = 0; i <= nrOfVGridPartitions; i++) {
            const double ypos = winh - padding - (pow(2.0,i) - 1) * (winh - 2 * padding - 1) / 255.0;
            cr->move_to(0, ypos);
            cr->line_to(winw, ypos);
            cr->stroke();
        }
    } else if (scopeType == Options::ScopeType::VECTORSCOPE_HC || scopeType == Options::ScopeType::VECTORSCOPE_HS) {
        // Vectorscope has no gridlines.
    } else if (drawMode == 0) {
        for (int i = 1; i < nrOfHGridPartitions; i++) {
            cr->move_to (padding,
                         i * static_cast<double>(winh) / nrOfHGridPartitions + 0.5);
            cr->line_to (winw - padding,
                         i * static_cast<double>(winh) / nrOfHGridPartitions + 0.5);
            cr->stroke ();
        }
    } else {
        for (int i = 1; i < nrOfHGridPartitions; i++) {
            cr->move_to (padding,
                         winh - HistogramScaling::log (winh, i * static_cast<double>(winh) / nrOfHGridPartitions) + 0.5);
            cr->line_to (winw - padding,
                         winh - HistogramScaling::log (winh, i * static_cast<double>(winh) / nrOfHGridPartitions) + 0.5);
            cr->stroke ();
        }
    }

    cr->unset_dash();

    MYREADERLOCK(wave_lock, wave_mutex)
    if (LUT_valid && (scopeType == Options::ScopeType::HISTOGRAM || scopeType == Options::ScopeType::HISTOGRAM_RAW)) {
        const bool rawMode = (scopeType == Options::ScopeType::HISTOGRAM_RAW);

        // For RAW mode use the other hists
        LUTu& rh = rawMode ? rhistRaw : rhist;
        LUTu& gh = rawMode ? ghistRaw : ghist;
        LUTu& bh = rawMode ? bhistRaw : bhist;

        // make double copies of LUT, one for faster access, another one to scale down the raw histos
        LUTu rhchanged(256), ghchanged(256), bhchanged(256);
        unsigned int lhisttemp[256] ALIGNED16 {0}, chisttemp[256] ALIGNED16 {0}, rhtemp[256] ALIGNED16 {0}, ghtemp[256] ALIGNED16 {0}, bhtemp[256] ALIGNED16 {0};
        const int scale = (rawMode ? 8 : 1);

        for (int i = 0; i < 256; i++) {
            if (needLuma && !rawMode) {
                lhisttemp[i] = lhist[i];
            }

            if (needChroma && !rawMode) {
                chisttemp[i] = chist[i];
            }

            if (needRed) {
                rhchanged[i] = rhtemp[i] = rh[i] / scale;
            }

            if (needGreen) {
                ghchanged[i] = ghtemp[i] = gh[i] / scale;
            }

            if (needBlue) {
                bhchanged[i] = bhtemp[i] = bh[i] / scale;
            }
        }

        // Compute the highest point of the histogram for scaling
        // Values at far left and right end (0 and 255) are handled differently

        unsigned int histheight = 0;

        for (int i = 1; i < 255; i++) {
            if (needLuma  && !rawMode && lhisttemp[i] > histheight) {
                histheight = lhisttemp[i];
            }

            if (needChroma  && !rawMode && chisttemp[i] > histheight) {
                histheight = chisttemp[i];
            }

            if (needRed && rhtemp[i] > histheight) {
                histheight = rhtemp[i];
            }

            if (needGreen && ghtemp[i] > histheight) {
                histheight = ghtemp[i];
            }

            if (needBlue && bhtemp[i] > histheight) {
                histheight = bhtemp[i];
            }
        }

        int realhistheight = histheight;

        if (realhistheight < winh - 2) {
            realhistheight = winh - 2;
        }

        cr->set_antialias (Cairo::ANTIALIAS_SUBPIXEL);
        cr->set_line_width (1.0);
        cr->set_operator (Cairo::OPERATOR_OVER);

        int ui = 0, oi = 0;

        if (needLuma && !rawMode) {
            drawCurve(cr, lhist, realhistheight, winw, winh);
            cr->set_source_rgba (0.65, 0.65, 0.65, 0.65);
            cr->fill ();
            drawMarks(cr, lhist, realhistheight, winw, ui, oi);
        }

        if (needChroma && !rawMode) {
            drawCurve(cr, chist, realhistheight, winw, winh);
            cr->set_source_rgb (0.9, 0.9, 0.);
            cr->stroke ();
            drawMarks(cr, chist, realhistheight, winw, ui, oi);
        }

        if (needRed) {
            drawCurve(cr, rhchanged, realhistheight, winw, winh);
            cr->set_source_rgb (1.0, 0.0, 0.0);
            cr->stroke ();
            drawMarks(cr, rhchanged, realhistheight, winw, ui, oi);
        }

        if (needGreen) {
            drawCurve(cr, ghchanged, realhistheight, winw, winh);
            cr->set_source_rgb (0.0, 1.0, 0.0);
            cr->stroke ();
            drawMarks(cr, ghchanged, realhistheight, winw, ui, oi);
        }

        if (needBlue) {
            drawCurve(cr, bhchanged, realhistheight, winw, winh);
            cr->set_source_rgb (0.0, 0.4, 1.0);
            cr->stroke ();
            drawMarks(cr, bhchanged, realhistheight, winw, ui, oi);
        }

    } else if (scopeType == Options::ScopeType::PARADE && rwave.getWidth() > 0) {
        drawParade(cr, winw, winh);
    } else if (scopeType == Options::ScopeType::WAVEFORM && rwave.getWidth() > 0) {
        drawWaveform(cr, winw, winh);
    } else if (scopeType == Options::ScopeType::VECTORSCOPE_HC || scopeType == Options::ScopeType::VECTORSCOPE_HS) {
        drawVectorscope(cr, winw, winh);
    }
    MYREADERLOCK_RELEASE(wave_lock);
}

bool HistogramArea::updatePointer(const int r, const int g, const int b, const rtengine::procparams::ColorManagementParams *cmp)
{
    // Do not update pointer values if pointer is not visible
    // (by user choice or according to scope type)
    if (!needPointer ||
            !(scopeType == Options::ScopeType::VECTORSCOPE_HC || scopeType == Options::ScopeType::VECTORSCOPE_HS)) {
        return false;
    }

    // Do not update pointer values if values are identical
    if (pointer_red == r && pointer_green == g && pointer_blue == b) {
        return false;
    }

    // Set pointer parameters to invalid if r = g = b = -1
    if (r == -1 || g == -1 || b == -1) {
        pointer_red = pointer_green = pointer_blue = -1;
        pointer_a = pointer_b = 0.;
        pointer_valid = false;
    } else {
        float L; // Unused
        pointer_red = r;
        pointer_green = g;
        pointer_blue = b;
        ImProcFunctions::rgb2lab(
            static_cast<std::uint8_t>(r),
            static_cast<std::uint8_t>(g),
            static_cast<std::uint8_t>(b),
            L, pointer_a, pointer_b,
            cmp != nullptr ? *cmp : App::get().fallbackColorCmp(),
            true);
        L /= 327.68f;
        pointer_a /= 327.68f;
        pointer_b /= 327.68f;
        pointer_valid = true;
    }

    return true;
}

void HistogramArea::on_realize ()
{
    Gtk::DrawingArea::on_realize();
    add_events(Gdk::POINTER_MOTION_MASK | Gdk::BUTTON_PRESS_MASK | Gdk::BUTTON_RELEASE_MASK);
}

void HistogramArea::drawCurve(const Cairo::RefPtr<Cairo::Context> &cr,
                              const LUTu & data, const double scale, const int hsize, const int vsize)
{
    cr->set_line_width(1.);
    cr->move_to (padding, vsize - 1);
    const double new_scale = scale <= 0.0 ? 0.001 : scale; // avoid division by zero and negative values

    for (int i = 0; i < 256; i++) {
        double val = data[i] * static_cast<double>(vsize) / new_scale;

        if (drawMode > 0) { // scale y for single and double log-scale
            val = HistogramScaling::log (static_cast<double>(vsize), val);
        }

        double iscaled = i;
        if (drawMode == 2) { // scale x for double log-scale
            iscaled = HistogramScaling::log (255.0, static_cast<double>(i));
        }

        double posX = padding + iscaled * (hsize - padding * 2.0) / 255.0;
        double posY = vsize - 2 + val * (4 - vsize) / vsize;

        cr->line_to (posX, posY);
    }

    cr->line_to (hsize - padding, vsize - 1);
}

void HistogramArea::drawMarks(const Cairo::RefPtr<Cairo::Context> &cr,
                              const LUTu & data, const double scale, const int wsize, int & ui, int & oi)
{
    if(data[0] > scale) {
        cr->rectangle(padding, (ui++) * 8., 8., 8.);
    }

    if(data[255] > scale) {
        cr->rectangle(wsize - 8. - padding, (oi++) * 8., 8., 8.);
    }

    cr->fill();
}

void HistogramArea::drawParade(const Cairo::RefPtr<Cairo::Context> &cr, const int w, const int h)
{
    // Arbitrary scale factor divided by current scale.
    const float scale = trace_brightness * 32.f * 255.f / waveform_scale;
    const int wave_width = rwave.getWidth();
    const int wave_height = rwave.getHeight();

    // See Cairo documentation on stride.
    const int cairo_stride = Cairo::ImageSurface::format_stride_for_width(Cairo::FORMAT_ARGB32, rwave.getWidth());
    const auto buffer_size = static_cast<std::vector<unsigned char>::size_type>(wave_height) * cairo_stride;

    if (parade_buffer_r_dirty && needRed) {
        parade_buffer_r.assign(buffer_size, 0);
        assert(parade_buffer_r.size() % 4 == 0);

        for (int val = 0; val < wave_height; val++) {
            const int* const r_row = rwave[val];
            std::uint32_t* const buffer_r_row = reinterpret_cast<uint32_t*>(parade_buffer_r.data() + (255 - val) * cairo_stride);
            for (int col = 0; col < wave_width; col++) {
                const unsigned char r = std::min<float>(scale * r_row[col], 0xff);
                if (r != 0) {
                    buffer_r_row[col] = (r << 16) | (r << 24);
                }
            }
        }

        parade_buffer_r_dirty = false;
    }

    if (parade_buffer_g_dirty && needGreen) {
        parade_buffer_g.assign(buffer_size, 0);
        assert(parade_buffer_g.size() % 4 == 0);

        for (int val = 0; val < wave_height; val++) {
            const int* const g_row = gwave[val];
            std::uint32_t* const buffer_g_row = reinterpret_cast<uint32_t*>(parade_buffer_g.data() + (255 - val) * cairo_stride);
            for (int col = 0; col < wave_width; col++) {
                const unsigned char g = std::min<float>(scale * g_row[col], 0xff);
                if (g != 0) {
                    buffer_g_row[col] = (g << 8) | (g << 24);
                }
            }
        }

        parade_buffer_g_dirty = false;
    }

    if (parade_buffer_b_dirty && needBlue) {
        parade_buffer_b.assign(buffer_size, 0);
        assert(parade_buffer_b.size() % 4 == 0);

        for (int val = 0; val < wave_height; val++) {
            const int* const b_row = bwave[val];
            std::uint32_t* const buffer_b_row = reinterpret_cast<uint32_t*>(parade_buffer_b.data() + (255 - val) * cairo_stride);
            for (int col = 0; col < wave_width; col++) {
                const unsigned char b = std::min<float>(scale * b_row[col], 0xff);
                if (b != 0) {
                    const unsigned char green = b / 2; // Make blue easier to see.
                    buffer_b_row[col] = b | (green << 8) | (b << 24);
                }
            }
        }

        parade_buffer_b_dirty = false;
    }

    if (wave_buffer_luma_dirty && needLuma) {
        wave_buffer_luma.assign(buffer_size, 0);
        assert(wave_buffer_luma.size() % 4 == 0);

        for (int val = 0; val < wave_height; val++) {
            const int* const l_row = lwave[val];
            std::uint32_t* const buffer_row =
                reinterpret_cast<uint32_t*>(wave_buffer_luma.data() + (255 - val) * cairo_stride);
            for (int col = 0; col < wave_width; col++) {
                const unsigned char l = std::min<float>(scale * l_row[col], 0xff);
                buffer_row[col] = l | (l << 8) | (l << 16) | (l << 24);
            }
        }

        wave_buffer_luma_dirty = false;
    }

    std::vector<unsigned char*> buffers;
    if (needLuma) {
        buffers.push_back(wave_buffer_luma.data());
    }
    if (needRed) {
        buffers.push_back(parade_buffer_r.data());
    }
    if (needGreen) {
        buffers.push_back(parade_buffer_g.data());
    }
    if (needBlue) {
        buffers.push_back(parade_buffer_b.data());
    }

    auto orig_matrix = cr->get_matrix();
    const double display_wave_width = static_cast<double>(w) / buffers.size();
    for (unsigned i = 0; i < buffers.size(); i++) {
        Cairo::RefPtr<Cairo::ImageSurface> surface;
        cr->translate(i * display_wave_width, padding);
        cr->scale(display_wave_width / wave_width, (h - 2 * padding) / wave_height);
        surface = Cairo::ImageSurface::create(
                      buffers[i], Cairo::FORMAT_ARGB32, wave_width, wave_height, cairo_stride);
        cr->set_source(surface, 0, 0);
        cr->set_operator(Cairo::OPERATOR_OVER);
        cr->paint();
        surface->finish();
        cr->set_matrix(orig_matrix);
    }
}

void HistogramArea::drawVectorscope(const Cairo::RefPtr<Cairo::Context> &cr, const int w, const int h)
{
    if (scopeType != Options::ScopeType::VECTORSCOPE_HC && scopeType != Options::ScopeType::VECTORSCOPE_HS) {
        return;
    }

    const auto& vect = (scopeType == Options::ScopeType::VECTORSCOPE_HC) ? vect_hc : vect_hs;
    auto& vect_buffer = (scopeType == Options::ScopeType::VECTORSCOPE_HC) ? vect_hc_buffer : vect_hs_buffer;
    auto& vect_buffer_dirty = (scopeType == Options::ScopeType::VECTORSCOPE_HC) ? vect_hc_buffer_dirty : vect_hs_buffer_dirty;

    const int vect_width = vect.getWidth();
    const int vect_height = vect.getHeight();

    // See Cairo documentation on stride.
    const int cairo_stride = Cairo::ImageSurface::format_stride_for_width(Cairo::FORMAT_ARGB32, vect_width);

    if (vect_buffer_dirty && vectorscope_scale > 0) {
        // Arbitrary scale factor multiplied by vectorscope area and divided by
        // current scale.
        const float scale = trace_brightness * 8.f * vect_width * vect_height / vectorscope_scale;

        if (vect_buffer.size() != static_cast<std::size_t>(cairo_stride) * vect_height) {
            vect_buffer.resize(static_cast<std::size_t>(cairo_stride) * vect_height);
        }

        assert(vect_buffer.size() % 4 == 0);

        for (int y = 0; y < vect_height; y++) {
            const int* const vect_row = vect[y];
            std::uint32_t* const buffer_row =
                reinterpret_cast<uint32_t*>(vect_buffer.data() + (vect_height - 1 - y) * cairo_stride);
            for (int x = 0; x < vect_width; x++) {
                const unsigned char value = std::min<float>(scale * vect_row[x], 0xff);
                buffer_row[x] = value | (value << 8) | (value << 16) | (value << 24);
            }
        }

        vect_buffer_dirty = false;
    }

    const bool fit_width =
        vect_width * (h - 2 * padding) > vect_height * (w - 2 * padding);
    const float scope_scale = fit_width ?
                              (w - 2 * padding) / vect_width : (h - 2 * padding) / vect_height;
    const float scope_size = (vectorscope_scale > 0) ?
                             scope_scale * std::max<double>(vect_width, vect_height) : std::min<float>(w, h) - 2 * padding;
    const float o_x = (w - scope_scale * vect_width) / 2;
    const float o_y = (h - scope_scale * vect_height) / 2;
    auto orig_matrix = cr->get_matrix();
    const double line_length = scope_size / 2.0;
    std::valarray<double> ch_ds(1);

    cr->translate(w / 2.0, h / 2.0);
    cr->set_line_width (1.0);
    cr->set_antialias(Cairo::ANTIALIAS_SUBPIXEL);
    ch_ds[0] = 4;

    if (scopeType == ScopeType::VECTORSCOPE_HS) { // Hue-Saturation.
        // RYGCBM lines.
        cr->set_line_width (2.0);
        constexpr double color_labels[6][3] = {
            {1, 0, 0}, // R
            {0, 1, 0}, // G
            {0, 0, 1}, // B
            {0, 1, 1}, // C
            {1, 0, 1}, // M
            {1, 1, 0}, // Y
        };
        for (int i = 0; i < 3; i++) {
            auto gradient = Cairo::LinearGradient::create(-line_length, 0, line_length, 0);
            const double (&color_1)[3] = color_labels[i];
            const double (&color_2)[3] = color_labels[i + 3];
            cr->set_source(gradient);
            gradient->add_color_stop_rgba(0, color_2[0], color_2[1], color_2[2], 0.5);
            gradient->add_color_stop_rgba(0.5, 1, 1, 1, 0.25);
            gradient->add_color_stop_rgba(1, color_1[0], color_1[1], color_1[2], 0.5);
            cr->move_to(-line_length, 0);
            cr->line_to(line_length, 0);
            cr->rotate_degrees(-120);
            cr->stroke();
        }
        cr->set_line_width (1.0);
        cr->set_source_rgba (1, 1, 1, 0.25);
        // 100% saturation circle.
        cr->arc(0, 0, scope_size / 2.0, 0, 2 * RT_PI);
        cr->stroke();
        // 25%, 50%, and 75% saturation.
        cr->set_dash(ch_ds, 0);
        for (int i = 1; i < 4; i++) {
            cr->arc(0, 0, i * scope_size / 8.0, 0, 2 * RT_PI);
            cr->stroke();
        }
        // HSV skin tone line derived from -I axis of YIQ.
        cr->rotate(-0.134900 * RT_PI);
        cr->move_to(0, 0);
        cr->line_to(line_length, 0);
        cr->stroke();
        cr->unset_dash();
    } else if (scopeType == ScopeType::VECTORSCOPE_HC) { // Hue-Chroma.
        // a and b axes.
        Cairo::RefPtr<Cairo::LinearGradient> gradient;
        cr->set_line_width (2.0);
        gradient = Cairo::LinearGradient::create(0, -line_length, 0, line_length);
        cr->set_source(gradient);
        gradient->add_color_stop_rgba(0, 1, 1, 0, 0.5); // "yellow"
        gradient->add_color_stop_rgba(0.5, 1, 1, 1, 0.25); // neutral
        gradient->add_color_stop_rgba(1, 0, 0, 1, 0.5); // "blue"
        cr->move_to(0, 0);
        cr->line_to(0, line_length);
        cr->move_to(0, 0);
        cr->line_to(0, -line_length);
        cr->stroke();
        gradient = Cairo::LinearGradient::create(-line_length, 0, line_length, 0);
        cr->set_source(gradient);
        gradient->add_color_stop_rgba(0, 0, 1, 0, 0.5); // "green"
        gradient->add_color_stop_rgba(0.5, 1, 1, 1, 0.25); // neutral
        gradient->add_color_stop_rgba(1, 1, 0, 1, 0.5); // "magenta"
        cr->move_to(0, 0);
        cr->line_to(line_length, 0);
        cr->move_to(0, 0);
        cr->line_to(-line_length, 0);
        cr->stroke();
        cr->set_source_rgba (1, 1, 1, 0.25);
        cr->set_line_width (1.0);
        // 25%, 50%, 75%, and 100% of standard chroma range.
        cr->set_dash(ch_ds, 0);
        for (int i = 1; i <= 4; i++) {
            cr->arc(0, 0, i * scope_size / 8.0, 0, 2 * RT_PI);
            cr->stroke();
        }
        // CIELAB skin tone line, approximated by 50% saturation and
        // value along the HSV skin tone line.
        cr->rotate(-0.321713 * RT_PI);
        cr->move_to(0, 0);
        cr->line_to(line_length, 0);
        cr->stroke();
        cr->unset_dash();
    }
    cr->set_matrix(orig_matrix);

    // Vectorscope trace.
    if (vectorscope_scale > 0) {
        Cairo::RefPtr<Cairo::ImageSurface> surface = Cairo::ImageSurface::create(
                    vect_buffer.data(), Cairo::FORMAT_ARGB32, vect_width, vect_height, cairo_stride);
        cr->translate(o_x, o_y);
        cr->scale(scope_scale, scope_scale);
        cr->set_source(surface, 0, 0);
        cr->set_operator(Cairo::OPERATOR_OVER);
        cr->paint();
        surface->finish();
        cr->set_matrix(orig_matrix);

        if (needPointer && pointer_valid) {
            float cx, cy;
            if (scopeType == ScopeType::VECTORSCOPE_HS) {
                float H, S, L;
                Color::rgb2hslfloat(pointer_red * 257.f, pointer_green * 257.f, pointer_blue * 257.f, H, S, L);
                cx = (w + scope_size * S * std::cos(H * 2 * RT_PI_F)) / 2;
                cy = (h - scope_size * S * std::sin(H * 2 * RT_PI_F)) / 2;
            } else {
                constexpr float ab_factor = 1.f / 256.f;
                cx = w / 2.f + scope_size * pointer_a * ab_factor;
                cy = h / 2.f - scope_size * pointer_b * ab_factor;
            }
            const float crosshair_size = 20.f;
            cr->set_source_rgba(1, 1, 1, 0.5);
            cr->move_to(cx - crosshair_size, cy);
            cr->line_to(cx + crosshair_size, cy);
            cr->move_to(cx, cy - crosshair_size);
            cr->line_to(cx, cy + crosshair_size);
            cr->stroke();
            cr->arc(cx, cy, 3, 0, 2 * RT_PI);
            cr->set_source_rgb(1, 1, 1);
            cr->fill_preserve();
            cr->set_source_rgb(0, 0, 0);
            cr->set_line_width (1.0);
            cr->stroke();
        }
    }
}

void HistogramArea::drawWaveform(const Cairo::RefPtr<Cairo::Context> &cr, const int w, const int h)
{
    // Arbitrary scale factor divided by current scale.
    const float scale = trace_brightness * 32.f * 255.f / waveform_scale;
    const int wave_width = rwave.getWidth();
    const int wave_height = rwave.getHeight();

    // See Cairo documentation on stride.
    const int cairo_stride = Cairo::ImageSurface::format_stride_for_width(Cairo::FORMAT_ARGB32, rwave.getWidth());
    const auto buffer_size = static_cast<std::vector<unsigned char>::size_type>(wave_height) * cairo_stride;

    if (wave_buffer_dirty && (needRed || needGreen || needBlue)) {
        wave_buffer.assign(buffer_size, 0);
        assert(wave_buffer.size() % 4 == 0);

        for (int val = 0; val < wave_height; val++) {
            const int* const r_row = rwave[val];
            const int* const g_row = gwave[val];
            const int* const b_row = bwave[val];
            std::uint32_t* const buffer_row = reinterpret_cast<uint32_t*>(wave_buffer.data() + (255 - val) * cairo_stride);
            for (int col = 0; col < wave_width; col++) {
                const unsigned char r = needRed ? std::min<float>(scale * r_row[col], 0xff) : 0;
                const unsigned char g = needGreen ? std::min<float>(scale * g_row[col], 0xff) : 0;
                const unsigned char b = needBlue ? std::min<float>(scale * b_row[col], 0xff) : 0;
                const unsigned char value = rtengine::max(r, g, b);
                if (value != 0) {
                    // Ensures correct order regardless of endianness.
                    buffer_row[col] = b | (g << 8) | (r << 16) | (value << 24);
                }
            }
        }

        wave_buffer_dirty = false;
    }

    if (wave_buffer_luma_dirty && needLuma) {
        wave_buffer_luma.assign(buffer_size, 0);
        assert(wave_buffer_luma.size() % 4 == 0);

        for (int val = 0; val < wave_height; val++) {
            const int* const l_row = lwave[val];
            std::uint32_t* const buffer_row =
                reinterpret_cast<uint32_t*>(wave_buffer_luma.data() + (255 - val) * cairo_stride);
            for (int col = 0; col < wave_width; col++) {
                const unsigned char l = std::min<float>(scale * l_row[col], 0xff);
                buffer_row[col] = l | (l << 8) | (l << 16) | (l << 24);
            }
        }

        wave_buffer_luma_dirty = false;
    }

    Cairo::RefPtr<Cairo::ImageSurface> surface;
    auto orig_matrix = cr->get_matrix();
    cr->translate(0, padding);
    cr->scale(static_cast<double>(w) / wave_width, (h - 2 * padding) / wave_height);
    if (needLuma) {
        surface = Cairo::ImageSurface::create(
                      wave_buffer_luma.data(), Cairo::FORMAT_ARGB32, wave_width, wave_height, cairo_stride);
        cr->set_source(surface, 0, 0);
        cr->set_operator(Cairo::OPERATOR_OVER);
        cr->paint();
        surface->finish();
    }
    if (needRed || needGreen || needBlue) {
        surface = Cairo::ImageSurface::create(
                      wave_buffer.data(), Cairo::FORMAT_ARGB32, wave_width, wave_height, cairo_stride);
        cr->set_source(surface, 0, 0);
        cr->set_operator(Cairo::OPERATOR_OVER);
        cr->paint();
        surface->finish();
    }
    cr->set_matrix(orig_matrix);
}

bool HistogramArea::on_draw(const ::Cairo::RefPtr< Cairo::Context> &cr)
{
    const Glib::RefPtr<Gtk::StyleContext> style = get_style_context();
    style->render_background(cr, 0, 0, get_width(), get_height());

    // Draw drawing area
    // Note: As drawing area surface is updated inside on_draw function, hidpi is automatically supported
    updateDrawingArea(cr);

    style->render_frame (cr, 0, 0, get_width(), get_height());

    return true;
}

bool HistogramArea::on_button_press_event (GdkEventButton* event)
{
    isPressed = true;
    movingPosition = event->x;

    if (
        event->type == GDK_2BUTTON_PRESS && event->button == 1
        && (scopeType == ScopeType::HISTOGRAM || scopeType == ScopeType::HISTOGRAM_RAW)
    ) {

        drawMode = (drawMode + 1) % 3;
        auto& options = App::get().mut_options();
        options.histogramDrawMode = (options.histogramDrawMode + 1) % 3;

        if (myDrawModeListener) {
            myDrawModeListener->toggleButtonMode ();
        }

        queue_draw ();
    }

    return true;
}

bool HistogramArea::on_button_release_event (GdkEventButton* event)
{
    isPressed = false;
    return true;
}

bool HistogramArea::on_motion_notify_event (GdkEventMotion* event)
{
    if (
        drawMode == 0
        && (scopeType == ScopeType::HISTOGRAM || scopeType == ScopeType::HISTOGRAM_RAW)
    ) {
        return false;
    }

    if (!isPressed) {
        return true;
    }

    if (scopeType == ScopeType::HISTOGRAM || scopeType == ScopeType::HISTOGRAM_RAW) { // Adjust log scale.
        double mod = 1 + (event->x - movingPosition) / get_width();

        factor /= mod;
        if (factor < 1.0)
            factor = 1.0;
        if (factor > 100.0)
            factor = 100.0;

        sigFactorChanged.emit(factor);

        queue_draw ();
    } else if (
        scopeType == ScopeType::PARADE
        || scopeType == ScopeType::WAVEFORM
        || scopeType == ScopeType::VECTORSCOPE_HC
        || scopeType == ScopeType::VECTORSCOPE_HS
    ) { // Adjust brightness.
        constexpr float RANGE = MAX_BRIGHT / MIN_BRIGHT;
        double dx = (event->x - movingPosition) / get_width();
        float new_brightness = LIM<float>(trace_brightness * pow(RANGE, dx), MIN_BRIGHT, MAX_BRIGHT);
        setBrightness(new_brightness);
        movingPosition = event->x;
    }

    return true;
}

float HistogramArea::getBrightness(void)
{
    return trace_brightness;
}

void HistogramArea::setBrightness(float brightness)
{
    brightness = LIM<float>(brightness, MIN_BRIGHT, MAX_BRIGHT);
    if (brightness != trace_brightness) {
        parade_buffer_r_dirty = parade_buffer_g_dirty = parade_buffer_b_dirty = wave_buffer_dirty = wave_buffer_luma_dirty = vect_hc_buffer_dirty = vect_hs_buffer_dirty = true;
        trace_brightness = brightness;
        queue_draw();

        signal_brightness_changed.emit(trace_brightness);
    }
}

HistogramArea::SignalBrightnessChanged HistogramArea::getBrighnessChangedSignal(void)
{
    return signal_brightness_changed;
}

HistogramArea::type_signal_factor_changed HistogramArea::signal_factor_changed()
{
    return sigFactorChanged;
}
