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LibGfx: Add support to draw radial gradients with an rotation angle

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Torstennator 2023-04-25 17:45:45 +02:00 • committed by Sam Atkins
parent 81dd29f713
commit abcfaca3da
2 changed files with 15 additions and 4 deletions
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17
Userland/Libraries/LibGfx/GradientPainting.cpp
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@ -213,18 +213,28 @@ static auto create_conic_gradient(ReadonlySpan<ColorStop> color_stops, FloatPoin
};
}
static auto create_radial_gradient(IntRect const& physical_rect, ReadonlySpan<ColorStop> color_stops, IntPoint center, IntSize size, Optional<float> repeat_length)
static auto create_radial_gradient(IntRect const& physical_rect, ReadonlySpan<ColorStop> color_stops, IntPoint center, IntSize size, Optional<float> repeat_length, Optional<float> rotation_angle = {})
{
// A conservative guesstimate on how many colors we need to generate:
auto max_dimension = max(physical_rect.width(), physical_rect.height());
auto max_visible_gradient = max(max_dimension / 2, min(size.width(), max_dimension));
GradientLine gradient_line(max_visible_gradient, color_stops, repeat_length);
auto center_point = FloatPoint { center }.translated(0.5, 0.5);
AffineTransform rotation_transform;
if (rotation_angle.has_value()) {
auto angle_as_radians = rotation_angle.value() * (AK::Pi<float> / 180);
rotation_transform.rotate_radians(angle_as_radians);
}
return Gradient {
move(gradient_line),
[=](int x, int y) {
// FIXME: See if there's a more efficient calculation we do there :^)
auto point = FloatPoint(x, y) - center_point;
if (rotation_angle.has_value())
point.transform_by(rotation_transform);
auto gradient_x = point.x() / size.width();
auto gradient_y = point.y() / size.height();
return AK::sqrt(gradient_x * gradient_x + gradient_y * gradient_y) * max_visible_gradient;
@ -257,12 +267,13 @@ void Painter::fill_rect_with_conic_gradient(IntRect const& rect, ReadonlySpan<Co
conic_gradient.paint(*this, a_rect);
}
void Painter::fill_rect_with_radial_gradient(IntRect const& rect, ReadonlySpan<ColorStop> color_stops, IntPoint center, IntSize size, Optional<float> repeat_length)
void Painter::fill_rect_with_radial_gradient(IntRect const& rect, ReadonlySpan<ColorStop> color_stops, IntPoint center, IntSize size, Optional<float> repeat_length, Optional<float> rotation_angle)
{
auto a_rect = to_physical(rect);
if (a_rect.intersected(clip_rect() * scale()).is_empty())
return;
auto radial_gradient = create_radial_gradient(a_rect, color_stops, center * scale(), size * scale(), repeat_length);
auto radial_gradient = create_radial_gradient(a_rect, color_stops, center * scale(), size * scale(), repeat_length, rotation_angle);
radial_gradient.paint(*this, a_rect);
}

2
Userland/Libraries/LibGfx/Painter.h
View file

@ -57,7 +57,7 @@ public:
void fill_rect_with_gradient(IntRect const&, Color gradient_start, Color gradient_end);
void fill_rect_with_linear_gradient(IntRect const&, ReadonlySpan<ColorStop>, float angle, Optional<float> repeat_length = {});
void fill_rect_with_conic_gradient(IntRect const&, ReadonlySpan<ColorStop>, IntPoint center, float start_angle, Optional<float> repeat_length = {});
void fill_rect_with_radial_gradient(IntRect const&, ReadonlySpan<ColorStop>, IntPoint center, IntSize size, Optional<float> repeat_length = {});
void fill_rect_with_radial_gradient(IntRect const&, ReadonlySpan<ColorStop>, IntPoint center, IntSize size, Optional<float> repeat_length = {}, Optional<float> rotation_angle = {});
void fill_rect_with_rounded_corners(IntRect const&, Color, int radius);
void fill_rect_with_rounded_corners(IntRect const&, Color, int top_left_radius, int top_right_radius, int bottom_right_radius, int bottom_left_radius);
void fill_ellipse(IntRect const&, Color);