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LibWeb: Support painting repeating-linear-gradient()s

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MacDue 2022-08-16 17:14:03 +01:00 • committed by Andreas Kling
parent ffdcc60b03
commit e294b7929a
2 changed files with 21 additions and 8 deletions
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28
Userland/Libraries/LibWeb/Painting/GradientPainting.cpp
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@ -120,7 +120,11 @@ LinearGradientData resolve_linear_gradient_data(Layout::Node const& node, Gfx::F
}
}
return { gradient_angle, resolved_color_stops };
Optional<float> repeat_length = {};
if (linear_gradient.is_repeating())
repeat_length = resolved_color_stops.last().position - resolved_color_stops.first().position;
return { gradient_angle, resolved_color_stops, repeat_length };
}
static float mix(float x, float y, float a)
@ -159,6 +163,7 @@ void paint_linear_gradient(PaintContext& context, Gfx::IntRect const& gradient_r
float sin_angle, cos_angle;
AK::sincos(angle, sin_angle, cos_angle);
// Full length of the gradient
auto length = calulate_gradient_length(gradient_rect.size(), sin_angle, cos_angle);
Gfx::FloatPoint offset { cos_angle * (length / 2), sin_angle * (length / 2) };
@ -196,17 +201,19 @@ void paint_linear_gradient(PaintContext& context, Gfx::IntRect const& gradient_r
};
Vector<Gfx::Color, 1024> gradient_line_colors;
auto int_length = round_to<int>(length);
gradient_line_colors.resize(int_length);
auto gradient_color_count = round_to<int>(data.repeat_length.value_or(length));
gradient_line_colors.resize(gradient_color_count);
auto& color_stops = data.color_stops;
for (int loc = 0; loc < int_length; loc++) {
auto start_offset = data.repeat_length.has_value() ? color_stops.first().position : 0.0f;
auto start_offset_int = round_to<int>(start_offset);
for (int loc = 0; loc < gradient_color_count; loc++) {
Gfx::Color gradient_color = color_mix(
color_stops[0].color,
color_stops[1].color,
color_stop_step(
color_stops[0],
color_stops[1],
loc));
loc + start_offset_int));
for (size_t i = 1; i < color_stops.size() - 1; i++) {
gradient_color = color_mix(
gradient_color,
@ -214,18 +221,23 @@ void paint_linear_gradient(PaintContext& context, Gfx::IntRect const& gradient_r
color_stop_step(
color_stops[i],
color_stops[i + 1],
loc));
loc + start_offset_int));
}
gradient_line_colors[loc] = gradient_color;
}
auto lookup_color = [&](int loc) {
return gradient_line_colors[clamp(loc, 0, int_length - 1)];
return gradient_line_colors[clamp(loc, 0, gradient_color_count - 1)];
};
for (int y = 0; y < gradient_rect.height(); y++) {
for (int x = 0; x < gradient_rect.width(); x++) {
auto loc = (x * cos_angle - (gradient_rect.height() - y) * -sin_angle) - rotated_start_point_x;
auto loc = (x * cos_angle - (gradient_rect.height() - y) * -sin_angle) - rotated_start_point_x - start_offset;
if (data.repeat_length.has_value()) {
loc = AK::fmod(loc, *data.repeat_length);
if (loc < 0)
loc = *data.repeat_length + loc;
}
// Blend between the two neighbouring colors (this fixes some nasty aliasing issues at small angles)
auto blend = loc - static_cast<int>(loc);
auto gradient_color = color_mix(lookup_color(loc - 1), lookup_color(loc), blend);

1
Userland/Libraries/LibWeb/Painting/GradientPainting.h
View file

@ -25,6 +25,7 @@ using ColorStopList = Vector<ColorStop, 4>;
struct LinearGradientData {
float gradient_angle;
ColorStopList color_stops;
Optional<float> repeat_length;
};
LinearGradientData resolve_linear_gradient_data(Layout::Node const&, Gfx::FloatSize const&, CSS::LinearGradientStyleValue const&);