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PixelPaint: Basic brush tool

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This patch adds a very basic implementation of the classic brush
tool. It features a wide brush with a falloff around the edges.
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BenJilks 2020-09-21 20:45:53 +01:00 • committed by Andreas Kling
parent 1208f3fd75
commit 5f15fb17d9
5 changed files with 167 additions and 0 deletions
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114
Applications/PixelPaint/BrushTool.cpp Normal file
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/*
* Copyright (c) 2020, Ben Jilks <benjyjilks@gmail.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "BrushTool.h"
#include "ImageEditor.h"
#include "Layer.h"
#include <LibGUI/Action.h>
#include <LibGUI/Painter.h>
#include <LibGfx/Color.h>
#include <LibGfx/Rect.h>
namespace PixelPaint {
BrushTool::BrushTool()
{
}
BrushTool::~BrushTool()
{
}
void BrushTool::on_mousedown(Layer&, GUI::MouseEvent& event, GUI::MouseEvent&)
{
if (event.button() != GUI::MouseButton::Left && event.button() != GUI::MouseButton::Right)
return;
m_last_position = event.position();
}
void BrushTool::on_mousemove(Layer& layer, GUI::MouseEvent& event, GUI::MouseEvent&)
{
if (!(event.buttons() & GUI::MouseButton::Left || event.buttons() & GUI::MouseButton::Right))
return;
draw_line(layer.bitmap(), m_editor->color_for(event), m_last_position, event.position());
layer.did_modify_bitmap(*m_editor->image());
m_last_position = event.position();
}
void BrushTool::draw_point(Gfx::Bitmap& bitmap, const Gfx::Color& color, const Gfx::IntPoint& point)
{
for (int y = point.y() - m_size; y < point.y() + m_size; y++) {
for (int x = point.x() - m_size; x < point.x() + m_size; x++) {
auto distance = point.distance_from({ x, y });
if (x < 0 || x >= bitmap.width() || y < 0 || y >= bitmap.height())
continue;
if (distance >= m_size)
continue;
auto falloff = (1.0 - (distance / (float)m_size)) * 0.2;
auto pixel_color = color;
pixel_color.set_alpha(falloff * 255);
bitmap.set_pixel(x, y, bitmap.get_pixel(x, y).blend(pixel_color));
}
}
}
void BrushTool::draw_line(Gfx::Bitmap& bitmap, const Gfx::Color& color, const Gfx::IntPoint& start, const Gfx::IntPoint& end)
{
int length_x = end.x() - start.x();
int length_y = end.y() - start.y();
float y_step = length_y == 0 ? 0 : (float)(length_y) / (float)(length_x);
if (y_step > abs(length_y))
y_step = abs(length_y);
if (y_step < -abs(length_y))
y_step = -abs(length_y);
if (y_step == 0 && start.x() == end.x())
return;
int start_x = start.x();
int end_x = end.x();
int start_y = start.y();
int end_y = end.y();
if (start_x > end_x) {
swap(start_x, end_x);
swap(start_y, end_y);
}
float y = start_y;
for (int x = start_x; x <= end_x; x++) {
int start_step_y = y;
int end_step_y = y + y_step;
if (start_step_y > end_step_y)
swap(start_step_y, end_step_y);
for (int i = start_step_y; i <= end_step_y; i++)
draw_point(bitmap, color, { x, i });
y += y_step;
}
}
}