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https://github.com/RGBCube/serenity
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LibGfx: Move FastBoxBlurFilter to its own .cpp file
This commit is contained in:
Andreas Kling
parent
f9a38fa693
commit
5726017414
3 changed files with 156 additions and 139 deletions
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@ -12,6 +12,7 @@ set(SOURCES
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DDSLoader.cpp
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DisjointRectSet.cpp
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Emoji.cpp
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Filters/FastBoxBlurFilter.cpp
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FontDatabase.cpp
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GIFLoader.cpp
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ICOLoader.cpp
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152
Userland/Libraries/LibGfx/Filters/FastBoxBlurFilter.cpp
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152
Userland/Libraries/LibGfx/Filters/FastBoxBlurFilter.cpp
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@ -0,0 +1,152 @@
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/*
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* Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibGfx/Filters/FastBoxBlurFilter.h>
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namespace Gfx {
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ALWAYS_INLINE static constexpr u8 red_value(Color color)
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{
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return (color.alpha() == 0) ? 0xFF : color.red();
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}
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ALWAYS_INLINE static constexpr u8 green_value(Color color)
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{
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return (color.alpha() == 0) ? 0xFF : color.green();
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}
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ALWAYS_INLINE static constexpr u8 blue_value(Color color)
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{
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return (color.alpha() == 0) ? 0xFF : color.blue();
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}
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FastBoxBlurFilter::FastBoxBlurFilter(Bitmap& bitmap)
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: m_bitmap(bitmap)
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{
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}
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// Based on the super fast blur algorithm by Quasimondo, explored here: https://stackoverflow.com/questions/21418892/understanding-super-fast-blur-algorithm
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void FastBoxBlurFilter::apply_single_pass(int radius)
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{
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VERIFY(radius >= 0);
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VERIFY(m_bitmap.format() == BitmapFormat::BGRA8888);
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int height = m_bitmap.height();
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int width = m_bitmap.width();
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int div = 2 * radius + 1;
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Vector<u8, 1024> intermediate_red;
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Vector<u8, 1024> intermediate_green;
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Vector<u8, 1024> intermediate_blue;
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Vector<u8, 1024> intermediate_alpha;
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intermediate_red.resize(width * height);
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intermediate_green.resize(width * height);
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intermediate_blue.resize(width * height);
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intermediate_alpha.resize(width * height);
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// First pass: vertical
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for (int y = 0; y < height; ++y) {
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size_t sum_red = 0;
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size_t sum_green = 0;
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size_t sum_blue = 0;
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size_t sum_alpha = 0;
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// Setup sliding window
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for (int i = -radius; i <= radius; ++i) {
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auto color_at_px = m_bitmap.get_pixel<StorageFormat::BGRA8888>(clamp(i, 0, width - 1), y);
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sum_red += red_value(color_at_px);
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sum_green += green_value(color_at_px);
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sum_blue += blue_value(color_at_px);
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sum_alpha += color_at_px.alpha();
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}
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// Slide horizontally
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for (int x = 0; x < width; ++x) {
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intermediate_red[y * width + x] = (sum_red / div);
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intermediate_green[y * width + x] = (sum_green / div);
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intermediate_blue[y * width + x] = (sum_blue / div);
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intermediate_alpha[y * width + x] = (sum_alpha / div);
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auto leftmost_x_coord = max(x - radius, 0);
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auto rightmost_x_coord = min(x + radius + 1, width - 1);
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auto leftmost_x_color = m_bitmap.get_pixel<StorageFormat::BGRA8888>(leftmost_x_coord, y);
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auto rightmost_x_color = m_bitmap.get_pixel<StorageFormat::BGRA8888>(rightmost_x_coord, y);
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sum_red -= red_value(leftmost_x_color);
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sum_red += red_value(rightmost_x_color);
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sum_green -= green_value(leftmost_x_color);
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sum_green += green_value(rightmost_x_color);
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sum_blue -= blue_value(leftmost_x_color);
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sum_blue += blue_value(rightmost_x_color);
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sum_alpha -= leftmost_x_color.alpha();
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sum_alpha += rightmost_x_color.alpha();
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}
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}
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// Second pass: horizontal
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for (int x = 0; x < width; ++x) {
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size_t sum_red = 0;
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size_t sum_green = 0;
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size_t sum_blue = 0;
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size_t sum_alpha = 0;
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// Setup sliding window
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for (int i = -radius; i <= radius; ++i) {
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int offset = clamp(i, 0, height - 1) * width + x;
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sum_red += intermediate_red[offset];
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sum_green += intermediate_green[offset];
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sum_blue += intermediate_blue[offset];
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sum_alpha += intermediate_alpha[offset];
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}
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for (int y = 0; y < height; ++y) {
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auto color = Color(
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sum_red / div,
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sum_green / div,
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sum_blue / div,
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sum_alpha / div);
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m_bitmap.set_pixel<StorageFormat::BGRA8888>(x, y, color);
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auto topmost_y_coord = max(y - radius, 0);
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auto bottommost_y_coord = min(y + radius + 1, height - 1);
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sum_red += intermediate_red[x + bottommost_y_coord * width];
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sum_red -= intermediate_red[x + topmost_y_coord * width];
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sum_green += intermediate_green[x + bottommost_y_coord * width];
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sum_green -= intermediate_green[x + topmost_y_coord * width];
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sum_blue += intermediate_blue[x + bottommost_y_coord * width];
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sum_blue -= intermediate_blue[x + topmost_y_coord * width];
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sum_alpha += intermediate_alpha[x + bottommost_y_coord * width];
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sum_alpha -= intermediate_alpha[x + topmost_y_coord * width];
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}
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}
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}
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// Math from here: http://blog.ivank.net/fastest-gaussian-blur.html
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void FastBoxBlurFilter::apply_three_passes(size_t radius)
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{
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if (!radius)
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return;
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constexpr size_t no_of_passes = 3;
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double w_ideal = sqrt((12 * radius * radius / (double)no_of_passes) + 1);
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int wl = floor(w_ideal);
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if (wl % 2 == 0)
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wl--;
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int wu = wl - 2;
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double m_ideal = (12 * radius * radius - no_of_passes * wl * wl - 4 * no_of_passes * wl - 3 * no_of_passes) / (double)(-4 * wl - 4);
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int m = round(m_ideal);
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for (size_t i = 0; i < no_of_passes; ++i) {
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int weighted_radius = (int)i < m ? wl : wu;
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if (weighted_radius < 2)
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continue;
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apply_single_pass((weighted_radius - 1) / 2);
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}
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}
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}
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@ -12,148 +12,12 @@ namespace Gfx {
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class FastBoxBlurFilter {
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public:
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FastBoxBlurFilter(Bitmap& bitmap)
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: m_bitmap(bitmap)
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{
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}
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FastBoxBlurFilter(Bitmap&);
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// Based on the super fast blur algorithm by Quasimondo, explored here: https://stackoverflow.com/questions/21418892/understanding-super-fast-blur-algorithm
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void apply_single_pass(int radius)
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{
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VERIFY(radius >= 0);
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VERIFY(m_bitmap.format() == BitmapFormat::BGRA8888);
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int height = m_bitmap.height();
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int width = m_bitmap.width();
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int div = 2 * radius + 1;
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Vector<u8, 1024> intermediate_red;
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Vector<u8, 1024> intermediate_green;
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Vector<u8, 1024> intermediate_blue;
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Vector<u8, 1024> intermediate_alpha;
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intermediate_red.resize(width * height);
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intermediate_green.resize(width * height);
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intermediate_blue.resize(width * height);
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intermediate_alpha.resize(width * height);
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// First pass: vertical
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for (int y = 0; y < height; ++y) {
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size_t sum_red = 0;
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size_t sum_green = 0;
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size_t sum_blue = 0;
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size_t sum_alpha = 0;
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// Setup sliding window
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for (int i = -radius; i <= radius; ++i) {
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auto color_at_px = m_bitmap.get_pixel<StorageFormat::BGRA8888>(clamp(i, 0, width - 1), y);
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sum_red += red_value(color_at_px);
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sum_green += green_value(color_at_px);
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sum_blue += blue_value(color_at_px);
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sum_alpha += color_at_px.alpha();
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}
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// Slide horizontally
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for (int x = 0; x < width; ++x) {
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intermediate_red[y * width + x] = (sum_red / div);
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intermediate_green[y * width + x] = (sum_green / div);
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intermediate_blue[y * width + x] = (sum_blue / div);
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intermediate_alpha[y * width + x] = (sum_alpha / div);
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auto leftmost_x_coord = max(x - radius, 0);
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auto rightmost_x_coord = min(x + radius + 1, width - 1);
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auto leftmost_x_color = m_bitmap.get_pixel<StorageFormat::BGRA8888>(leftmost_x_coord, y);
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auto rightmost_x_color = m_bitmap.get_pixel<StorageFormat::BGRA8888>(rightmost_x_coord, y);
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sum_red -= red_value(leftmost_x_color);
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sum_red += red_value(rightmost_x_color);
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sum_green -= green_value(leftmost_x_color);
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sum_green += green_value(rightmost_x_color);
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sum_blue -= blue_value(leftmost_x_color);
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sum_blue += blue_value(rightmost_x_color);
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sum_alpha -= leftmost_x_color.alpha();
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sum_alpha += rightmost_x_color.alpha();
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}
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}
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// Second pass: horizontal
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for (int x = 0; x < width; ++x) {
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size_t sum_red = 0;
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size_t sum_green = 0;
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size_t sum_blue = 0;
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size_t sum_alpha = 0;
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// Setup sliding window
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for (int i = -radius; i <= radius; ++i) {
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int offset = clamp(i, 0, height - 1) * width + x;
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sum_red += intermediate_red[offset];
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sum_green += intermediate_green[offset];
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sum_blue += intermediate_blue[offset];
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sum_alpha += intermediate_alpha[offset];
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}
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for (int y = 0; y < height; ++y) {
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auto color = Color(
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sum_red / div,
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sum_green / div,
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sum_blue / div,
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sum_alpha / div);
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m_bitmap.set_pixel<StorageFormat::BGRA8888>(x, y, color);
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auto topmost_y_coord = max(y - radius, 0);
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auto bottommost_y_coord = min(y + radius + 1, height - 1);
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sum_red += intermediate_red[x + bottommost_y_coord * width];
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sum_red -= intermediate_red[x + topmost_y_coord * width];
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sum_green += intermediate_green[x + bottommost_y_coord * width];
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sum_green -= intermediate_green[x + topmost_y_coord * width];
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sum_blue += intermediate_blue[x + bottommost_y_coord * width];
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sum_blue -= intermediate_blue[x + topmost_y_coord * width];
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sum_alpha += intermediate_alpha[x + bottommost_y_coord * width];
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sum_alpha -= intermediate_alpha[x + topmost_y_coord * width];
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}
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}
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}
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// Math from here: http://blog.ivank.net/fastest-gaussian-blur.html
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void apply_three_passes(size_t radius)
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{
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if (!radius)
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return;
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constexpr size_t no_of_passes = 3;
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double w_ideal = sqrt((12 * radius * radius / (double)no_of_passes) + 1);
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int wl = floor(w_ideal);
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if (wl % 2 == 0)
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wl--;
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int wu = wl - 2;
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double m_ideal = (12 * radius * radius - no_of_passes * wl * wl - 4 * no_of_passes * wl - 3 * no_of_passes) / (double)(-4 * wl - 4);
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int m = round(m_ideal);
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for (size_t i = 0; i < no_of_passes; ++i) {
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int weighted_radius = (int)i < m ? wl : wu;
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if (weighted_radius < 2)
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continue;
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apply_single_pass((weighted_radius - 1) / 2);
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}
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}
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void apply_single_pass(int radius);
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void apply_three_passes(size_t radius);
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private:
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ALWAYS_INLINE static u8 red_value(Color color)
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{
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return (color.alpha() == 0) ? 0xFF : color.red();
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}
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ALWAYS_INLINE static u8 green_value(Color color)
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{
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return (color.alpha() == 0) ? 0xFF : color.green();
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}
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ALWAYS_INLINE static u8 blue_value(Color color)
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{
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return (color.alpha() == 0) ? 0xFF : color.blue();
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}
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Bitmap& m_bitmap;
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};
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