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-rw-r--r--dggui/pixelbuffer.cc369
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diff --git a/dggui/pixelbuffer.cc b/dggui/pixelbuffer.cc
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ * pixelbuffer.cc
+ *
+ * Thu Nov 10 09:00:38 CET 2011
+ * Copyright 2011 Bent Bisballe Nyeng
+ * deva@aasimon.org
+ ****************************************************************************/
+
+/*
+ * This file is part of DrumGizmo.
+ *
+ * DrumGizmo is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * DrumGizmo 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with DrumGizmo; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+#include "pixelbuffer.h"
+
+#include <cassert>
+
+#include <cstdlib>
+#include <cstring>
+#include <algorithm>
+
+namespace GUI
+{
+
+PixelBuffer::PixelBuffer(std::size_t width, std::size_t height)
+{
+ realloc(width, height);
+}
+
+PixelBuffer::~PixelBuffer()
+{
+}
+
+void PixelBuffer::realloc(std::size_t width, std::size_t height)
+{
+ buf_data.resize(width * height * 3);
+ buf = buf_data.data();
+ this->width = width;
+ this->height = height;
+}
+
+void PixelBuffer::blendLine(std::size_t x, std::size_t y,
+ const std::uint8_t* line, std::size_t len)
+{
+ std::uint8_t* target = buf + (x + y * width) * 3;
+ while(len)
+ {
+ if(line[3] == 0xff)
+ {
+ std::memcpy(target, line, 3);
+ }
+ else
+ {
+ unsigned int a = line[3];
+ unsigned int b = 255 - a;
+
+ target[0] = (std::uint8_t)((line[0] * a + target[0] * b) / 255);
+ target[1] = (std::uint8_t)((line[1] * a + target[1] * b) / 255);
+ target[2] = (std::uint8_t)((line[2] * a + target[2] * b) / 255);
+ }
+ target += 3;
+ line += 4;
+ --len;
+ }
+}
+
+Rect PixelBuffer::updateBuffer(std::vector<PixelBufferAlpha*>& pixel_buffers)
+{
+ bool has_dirty_rect{false};
+ Rect dirty_rect;
+
+ for(const auto& pixel_buffer : pixel_buffers)
+ {
+ if(pixel_buffer->dirty)
+ {
+ auto x1 = (std::size_t)std::max(pixel_buffer->x, 0);
+ auto x2 = (std::size_t)std::max((pixel_buffer->x + (int)pixel_buffer->width), 0);
+ auto y1 = (std::size_t)std::max(pixel_buffer->y, 0);
+ auto y2 = (std::size_t)std::max((pixel_buffer->y + (int)pixel_buffer->height), 0);
+
+ pixel_buffer->dirty = false;
+ if(!has_dirty_rect)
+ {
+ // Insert this area:
+ dirty_rect = {x1, y1, x2, y2};
+ has_dirty_rect = true;
+ }
+ else
+ {
+ // Expand existing area:
+ auto x1_0 = dirty_rect.x1;
+ auto y1_0 = dirty_rect.y1;
+ auto x2_0 = dirty_rect.x2;
+ auto y2_0 = dirty_rect.y2;
+ dirty_rect = {
+ (x1_0 < x1) ? x1_0 : x1,
+ (y1_0 < y1) ? y1_0 : y1,
+ (x2_0 > x2) ? x2_0 : x2,
+ (y2_0 > y2) ? y2_0 : y2
+ };
+ }
+ }
+
+ if(pixel_buffer->has_last)
+ {
+ auto x1 = (std::size_t)pixel_buffer->last_x;
+ auto x2 = (std::size_t)(pixel_buffer->last_x + pixel_buffer->last_width);
+ auto y1 = (std::size_t)pixel_buffer->last_y;
+ auto y2 = (std::size_t)(pixel_buffer->last_y + pixel_buffer->last_height);
+
+ pixel_buffer->has_last = false;
+ if(!has_dirty_rect)
+ {
+ // Insert this area:
+ dirty_rect = {x1, y1, x2, y2};
+ has_dirty_rect = true;
+ }
+ else
+ {
+ // Expand existing area:
+ auto x1_0 = dirty_rect.x1;
+ auto y1_0 = dirty_rect.y1;
+ auto x2_0 = dirty_rect.x2;
+ auto y2_0 = dirty_rect.y2;
+ dirty_rect = {
+ (x1_0 < x1) ? x1_0 : x1,
+ (y1_0 < y1) ? y1_0 : y1,
+ (x2_0 > x2) ? x2_0 : x2,
+ (y2_0 > y2) ? y2_0 : y2
+ };
+ }
+ }
+ }
+
+ if(!has_dirty_rect)
+ {
+ return {};
+ }
+
+ for(const auto& pixel_buffer : pixel_buffers)
+ {
+ if(!pixel_buffer->visible)
+ {
+ continue;
+ }
+
+ int update_width = pixel_buffer->width;
+ int update_height = pixel_buffer->height;
+
+ // Skip buffer if not inside window.
+ if(((int)width < pixel_buffer->x) ||
+ ((int)height < pixel_buffer->y))
+ {
+ continue;
+ }
+
+ if(update_width > ((int)width - pixel_buffer->x))
+ {
+ update_width = ((int)width - pixel_buffer->x);
+ }
+
+ if(update_height > ((int)height - pixel_buffer->y))
+ {
+ update_height = ((int)height - pixel_buffer->y);
+ }
+
+ auto from_x = (int)dirty_rect.x1 - pixel_buffer->x;
+ from_x = std::max(0, from_x);
+ auto from_y = (int)dirty_rect.y1 - pixel_buffer->y;
+ from_y = std::max(0, from_y);
+
+ auto to_x = (int)dirty_rect.x2 - pixel_buffer->x;
+ to_x = std::min(to_x, (int)update_width);
+ auto to_y = (int)dirty_rect.y2 - pixel_buffer->y;
+ to_y = std::min(to_y, (int)update_height);
+
+ if(to_x < from_x)
+ {
+ continue;
+ }
+
+ for(int y = from_y; y < to_y; y++)
+ {
+ blendLine(pixel_buffer->x + from_x,
+ pixel_buffer->y + y,
+ pixel_buffer->getLine(from_x, y),
+ to_x - from_x);
+ }
+ }
+
+ dirty_rect.x2 = std::min(width, dirty_rect.x2);
+ dirty_rect.y2 = std::min(height, dirty_rect.y2);
+
+ // Make sure we don't try to paint a rect backwards.
+ if(dirty_rect.x1 > dirty_rect.x2)
+ {
+ std::swap(dirty_rect.x1, dirty_rect.x2);
+ }
+
+ if(dirty_rect.y1 > dirty_rect.y2)
+ {
+ std::swap(dirty_rect.y1, dirty_rect.y2);
+ }
+
+ return dirty_rect;
+}
+
+PixelBufferAlpha::PixelBufferAlpha(std::size_t width, std::size_t height)
+{
+ realloc(width, height);
+}
+
+PixelBufferAlpha::~PixelBufferAlpha()
+{
+}
+
+void PixelBufferAlpha::realloc(std::size_t width, std::size_t height)
+{
+ buf_data.resize(width * height * 4);
+ buf = buf_data.data();
+ this->width = width;
+ this->height = height;
+ clear();
+}
+
+void PixelBufferAlpha::clear()
+{
+ std::memset(buf, 0, width * height * 4);
+}
+
+void PixelBufferAlpha::setPixel(std::size_t x, std::size_t y, const Colour& c)
+{
+ std::uint8_t* pixel = buf + (x + y * width) * 4;
+ std::memcpy(pixel, c.data(), 4);
+}
+
+void PixelBufferAlpha::writeLine(std::size_t x, std::size_t y,
+ const std::uint8_t* line, std::size_t len)
+{
+ if(x >= width || y >= height)
+ {
+ return;
+ }
+
+ if(x + len > width)
+ {
+ len = width - x;
+ }
+
+ auto offset = buf + (x + y * width) * 4;
+
+ std::memcpy(offset, line, len * 4);
+}
+
+
+// SIMD: https://github.com/WojciechMula/toys/blob/master/blend_32bpp/blend_32bpp.c
+// Alpha blending: http://en.wikipedia.org/wiki/Alpha_compositing
+
+void PixelBufferAlpha::blendLine(std::size_t x, std::size_t y,
+ const std::uint8_t* line, std::size_t len)
+{
+ if(x >= width || y >= height)
+ {
+ return;
+ }
+
+ if(x + len > width)
+ {
+ len = width - x;
+ }
+
+ int a, b;
+ std::uint8_t* target = buf + (x + y * width) * 4;
+ while(len)
+ {
+ if(line[3] == 0xff)
+ {
+ const std::uint8_t* end = line;
+ while(end[3] == 0xff && end < line + len * 4)
+ {
+ end += 4;
+ }
+ auto chunk_len = end - line;
+ std::memcpy(target, line, chunk_len);
+ line += chunk_len;
+ target += chunk_len;
+ len -= chunk_len / 4;
+ continue;
+ }
+ else if(line[3] == 0)
+ {
+ // Do nothing
+ }
+ else
+ {
+ a = line[3];
+ b = target[3] * (255 - a) / 255;
+
+ target[0] = (line[0] * a + target[0] * b) / (a + b);
+ target[1] = (line[1] * a + target[1] * b) / (a + b);
+ target[2] = (line[2] * a + target[2] * b) / (a + b);
+ target[3] = (int)target[3] + line[3] * (255 - target[3]) / 255;
+ }
+
+ line += 4;
+ target += 4;
+ --len;
+ }
+}
+
+void PixelBufferAlpha::addPixel(std::size_t x, std::size_t y, const Colour& c)
+{
+ if(x >= width || y >= height)
+ {
+ return; // out of bounds
+ }
+
+ const std::uint8_t* colour = c.data();
+
+ if(colour[3] == 0)
+ {
+ return;
+ }
+
+ int a, b;
+ std::uint8_t* target = buf + (x + y * width) * 4;
+
+ if(colour[3] == 0xff)
+ {
+ std::memcpy(target, colour, 4);
+ }
+ else
+ {
+ a = colour[3];
+ b = target[3] * (255 - a) / 255;
+
+ target[0] = (colour[0] * a + target[0] * b) / (a + b);
+ target[1] = (colour[1] * a + target[1] * b) / (a + b);
+ target[2] = (colour[2] * a + target[2] * b) / (a + b);
+ target[3] = (int)target[3] + colour[3] * (255 - target[3]) / 255;
+ }
+}
+
+const Colour& PixelBufferAlpha::pixel(std::size_t x, std::size_t y) const
+{
+ static Colour c;
+ std::memcpy(c.data(), buf + (x + y * width) * 4, 4);
+ return c;
+}
+
+const std::uint8_t* PixelBufferAlpha::getLine(std::size_t x, std::size_t y) const
+{
+ return buf + (x + y * width) * 4;
+}
+
+} // GUI::
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