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Painter: Templatize the inner loop of draw_scaled_bitmap().

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Use templates to specialize draw_scaled_bitmap() so we don't have to blend()
for source without alpha, and also inline the GraphicsBitmap::get_pixel()
logic so we don't have to branch on the bitmap format on every iteration.

This is another ~30% speedup on top of the previous changes. :^)
This commit is contained in:
Andreas Kling 2019-05-11 03:53:28 +02:00
parent 01a1194e6f
commit 91a4b60d66
1 changed files with 43 additions and 9 deletions
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52
SharedGraphics/Painter.cpp
View file

@ -9,6 +9,18 @@
#include <stdio.h>
#include <math.h>
template<GraphicsBitmap::Format format = GraphicsBitmap::Format::Invalid>
static ALWAYS_INLINE Color get_pixel(const GraphicsBitmap& bitmap, int x, int y)
{
if constexpr (format == GraphicsBitmap::Format::Indexed8)
return bitmap.palette_color(bitmap.bits(y)[x]);
if constexpr (format == GraphicsBitmap::Format::RGB32)
return Color::from_rgb(bitmap.scanline(y)[x]);
if constexpr (format == GraphicsBitmap::Format::RGBA32)
return Color::from_rgba(bitmap.scanline(y)[x]);
return bitmap.get_pixel(x, y);
}
Painter::Painter(GraphicsBitmap& bitmap)
: m_target(bitmap)
{
@ -336,6 +348,24 @@ void Painter::blit(const Point& position, const GraphicsBitmap& source, const Re
ASSERT_NOT_REACHED();
}
template<bool has_alpha_channel, typename GetPixel>
ALWAYS_INLINE static void do_draw_scaled_bitmap(GraphicsBitmap& target, const Rect& dst_rect, const Rect& clipped_rect, const GraphicsBitmap& source, int hscale, int vscale, GetPixel get_pixel)
{
for (int y = clipped_rect.top(); y <= clipped_rect.bottom(); ++y) {
auto* scanline = (Color*)target.scanline(y);
for (int x = clipped_rect.left(); x <= clipped_rect.right(); ++x) {
auto scaled_x = ((x - dst_rect.x()) * hscale) >> 16;
auto scaled_y = ((y - dst_rect.y()) * vscale) >> 16;
auto src_pixel = get_pixel(source, scaled_x, scaled_y);
if constexpr (has_alpha_channel) {
scanline[x] = scanline[x].blend(src_pixel);
} else
scanline[x] = src_pixel;
}
}
}
void Painter::draw_scaled_bitmap(const Rect& a_dst_rect, const GraphicsBitmap& source, const Rect& src_rect)
{
auto dst_rect = a_dst_rect;
@ -352,15 +382,19 @@ void Painter::draw_scaled_bitmap(const Rect& a_dst_rect, const GraphicsBitmap& s
int hscale = (src_rect.width() << 16) / dst_rect.width();
int vscale = (src_rect.height() << 16) / dst_rect.height();
for (int y = clipped_rect.top(); y <= clipped_rect.bottom(); ++y) {
auto* scanline = (Color*)m_target->scanline(y);
for (int x = clipped_rect.left(); x <= clipped_rect.right(); ++x) {
auto scaled_x = ((x - dst_rect.x()) * hscale) >> 16;
auto scaled_y = ((y - dst_rect.y()) * vscale) >> 16;
auto src_pixel = source.get_pixel(scaled_x, scaled_y);
scanline[x] = scanline[x].blend(src_pixel);
if (source.has_alpha_channel()) {
switch (source.format()) {
case GraphicsBitmap::Format::RGB32: do_draw_scaled_bitmap<true>(*m_target, dst_rect, clipped_rect, source, hscale, vscale, get_pixel<GraphicsBitmap::Format::RGB32>); break;
case GraphicsBitmap::Format::RGBA32: do_draw_scaled_bitmap<true>(*m_target, dst_rect, clipped_rect, source, hscale, vscale, get_pixel<GraphicsBitmap::Format::RGB32>); break;
case GraphicsBitmap::Format::Indexed8: do_draw_scaled_bitmap<true>(*m_target, dst_rect, clipped_rect, source, hscale, vscale, get_pixel<GraphicsBitmap::Format::Indexed8>); break;
default: do_draw_scaled_bitmap<true>(*m_target, dst_rect, clipped_rect, source, hscale, vscale, get_pixel<GraphicsBitmap::Format::Invalid>); break;
}
} else {
switch (source.format()) {
case GraphicsBitmap::Format::RGB32: do_draw_scaled_bitmap<false>(*m_target, dst_rect, clipped_rect, source, hscale, vscale, get_pixel<GraphicsBitmap::Format::RGB32>); break;
case GraphicsBitmap::Format::RGBA32: do_draw_scaled_bitmap<false>(*m_target, dst_rect, clipped_rect, source, hscale, vscale, get_pixel<GraphicsBitmap::Format::RGB32>); break;
case GraphicsBitmap::Format::Indexed8: do_draw_scaled_bitmap<false>(*m_target, dst_rect, clipped_rect, source, hscale, vscale, get_pixel<GraphicsBitmap::Format::Indexed8>); break;
default: do_draw_scaled_bitmap<false>(*m_target, dst_rect, clipped_rect, source, hscale, vscale, get_pixel<GraphicsBitmap::Format::Invalid>); break;
}
}
}