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/*
* Copyright (c) 2022, Torsten Engelmann
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "HistogramWidget.h"
#include "Image.h"
#include "ImageEditor.h"
#include "Layer.h"
#include <LibGUI/Painter.h>
#include <LibGfx/Palette.h>
#include <LibGfx/Path.h>
REGISTER_WIDGET(PixelPaint, HistogramWidget);
namespace PixelPaint {
ErrorOr<void> HistogramWidget::rebuild_histogram_data()
{
if (!m_image)
return {};
auto full_bitmap = TRY(m_image->compose_bitmap(Gfx::BitmapFormat::BGRA8888));
m_data.red.clear_with_capacity();
m_data.green.clear_with_capacity();
m_data.blue.clear_with_capacity();
m_data.brightness.clear_with_capacity();
for (int i = 0; i < 256; i++) {
m_data.red.append(0);
m_data.green.append(0);
m_data.blue.append(0);
m_data.brightness.append(0);
}
Color pixel_color;
for (int x = 0; x < full_bitmap->width(); x++) {
for (int y = 0; y < full_bitmap->height(); y++) {
pixel_color = full_bitmap->get_pixel(x, y);
if (!pixel_color.alpha())
continue;
m_data.red[pixel_color.red()]++;
m_data.green[pixel_color.green()]++;
m_data.blue[pixel_color.blue()]++;
m_data.brightness[pixel_color.luminosity()]++;
}
}
int max_brightness_frequency = 0;
int max_color_frequency = 0;
for (int i = 0; i < 256; i++) {
if (m_data.red[i] > max_color_frequency)
max_color_frequency = m_data.red[i];
if (m_data.green[i] > max_color_frequency)
max_color_frequency = m_data.green[i];
if (m_data.blue[i] > max_color_frequency)
max_color_frequency = m_data.blue[i];
if (m_data.brightness[i] > max_brightness_frequency)
max_brightness_frequency = m_data.brightness[i];
}
// Scale the frequency values to fit the widgets height.
auto widget_height = height();
for (int i = 0; i < 256; i++) {
m_data.red[i] = m_data.red[i] != 0 ? (static_cast<float>(m_data.red[i]) / max_color_frequency) * widget_height : 0;
m_data.green[i] = m_data.green[i] != 0 ? (static_cast<float>(m_data.green[i]) / max_color_frequency) * widget_height : 0;
m_data.blue[i] = m_data.blue[i] != 0 ? (static_cast<float>(m_data.blue[i]) / max_color_frequency) * widget_height : 0;
m_data.brightness[i] = m_data.brightness[i] != 0 ? (static_cast<float>(m_data.brightness[i]) / max_brightness_frequency) * widget_height : 0;
}
return {};
}
void HistogramWidget::paint_event(GUI::PaintEvent& event)
{
GUI::Painter painter(*this);
painter.add_clip_rect(event.rect());
if (!m_image)
return;
int bottom_line = height() - 1;
float step_width = static_cast<float>(width()) / 256;
Gfx::Path brightness_path;
Gfx::Path red_channel_path;
Gfx::Path green_channel_path;
Gfx::Path blue_channel_path;
red_channel_path.move_to({ 0, bottom_line - m_data.red[0] });
green_channel_path.move_to({ 0, bottom_line - m_data.green[0] });
blue_channel_path.move_to({ 0, bottom_line - m_data.blue[0] });
brightness_path.move_to({ 0, bottom_line });
brightness_path.line_to({ 0, bottom_line });
float current_x_as_float = 0;
int current_x_as_int = 0;
int last_drawn_x = -1;
for (int data_column = 0; data_column < 256; data_column++) {
current_x_as_int = static_cast<int>(current_x_as_float);
// we would like to skip values that map to the same x position as it does not look so good in the final result
if (current_x_as_int == last_drawn_x) {
current_x_as_float += step_width;
continue;
}
red_channel_path.line_to({ current_x_as_int, bottom_line - m_data.red[data_column] });
green_channel_path.line_to({ current_x_as_int, bottom_line - m_data.green[data_column] });
blue_channel_path.line_to({ current_x_as_int, bottom_line - m_data.blue[data_column] });
brightness_path.line_to({ current_x_as_int, bottom_line - m_data.brightness[data_column] });
current_x_as_float += step_width;
last_drawn_x = current_x_as_int;
}
brightness_path.line_to({ last_drawn_x, bottom_line });
brightness_path.close();
painter.fill_path(brightness_path, Color::MidGray, Gfx::Painter::WindingRule::EvenOdd);
painter.stroke_path(red_channel_path, Color(Color::NamedColor::Red).with_alpha(90), 2);
painter.stroke_path(green_channel_path, Color(Color::NamedColor::Green).with_alpha(90), 2);
painter.stroke_path(blue_channel_path, Color(Color::NamedColor::Blue).with_alpha(90), 2);
if (m_color_at_mouseposition != Color::Transparent) {
int x = m_color_at_mouseposition.luminosity() * step_width;
painter.draw_line({ x, 0 }, { x, bottom_line }, Color::from_hsl(45, 1, .7), 1);
}
}
void HistogramWidget::image_changed()
{
(void)rebuild_histogram_data();
update();
}
}
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