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LibGfx: Add Painter::fill_pixels()

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This function fills a region of pixels with the result of a callback
function. This is an alternative to a for loop that repeatedly calls
Painter::set_pixel(), which can get very expensive due to the clipping
checks set_pixel() does each call.
This commit is contained in:
MacDue 2022-12-24 14:18:53 +00:00 • committed by Andreas Kling
parent 7e701f6256
commit ca01017f32
2 changed files with 30 additions and 1 deletions
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9
Userland/Libraries/LibGfx/Painter.cpp
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@ -1842,7 +1842,14 @@ void Painter::set_pixel(IntPoint p, Color color, bool blend)
// scaling and call set_pixel() -- do not scale the pixel.
if (!clip_rect().contains(point / scale()))
return;
auto& dst = m_target->scanline(point.y())[point.x()];
set_physical_pixel(point, color, blend);
}
void Painter::set_physical_pixel(IntPoint physical_point, Color color, bool blend)
{
// This function should only be called after translation, clipping, etc has been handled elsewhere
// if not use set_pixel().
auto& dst = m_target->scanline(physical_point.y())[physical_point.x()];
if (!blend || color.alpha() == 255)
dst = color.value();
else if (color.alpha())

22
Userland/Libraries/LibGfx/Painter.h
View file

@ -162,6 +162,27 @@ public:
int scale() const { return state().scale; }
template<typename TGetPixelCallback>
void fill_pixels(Gfx::IntRect const& region, TGetPixelCallback callback, bool blend = false)
{
// Note: This function paints physical pixels and therefore does not make sense when
// called on a scaled painter. Scaling the region painted may break the caller (this
// would be the case for gradients in LibWeb), and if you scale the pixels (to squares)
// then this is no longer filling pixels.
VERIFY(scale() == 1);
auto paint_region = region.translated(translation());
auto clipped_region = paint_region.intersected(clip_rect());
if (clipped_region.is_empty())
return;
auto start_offset = clipped_region.location() - paint_region.location();
for (int y = 0; y < clipped_region.height(); y++) {
for (int x = 0; x < clipped_region.width(); x++) {
auto pixel = callback(IntPoint(x, y).translated(start_offset));
set_physical_pixel(clipped_region.location().translated(x, y), pixel, blend);
}
}
}
protected:
IntRect to_physical(IntRect const& r) const { return r.translated(translation()) * scale(); }
IntPoint to_physical(IntPoint p) const { return p.translated(translation()) * scale(); }
@ -170,6 +191,7 @@ protected:
void fill_rect_with_draw_op(IntRect const&, Color);
void blit_with_opacity(IntPoint, Gfx::Bitmap const&, IntRect const& src_rect, float opacity, bool apply_alpha = true);
void draw_physical_pixel(IntPoint, Color, int thickness = 1);
void set_physical_pixel(IntPoint, Color color, bool blend);
struct State {
Font const* font;