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Auto merge of #7370 - bjwbell:bugfix-unequal-borders, r=pcwalton
gfx: Border radius support for asymmetric sized borders When the border-top/right/bottom/left-widths are not equal, the angle on the border corner arc separating the borders isn't PI/4. For instance if the top border width is much larger than the left border width then most of the border corner should be drawn using the top border color. This change adds support for calculating the correct angle in the border corner arc for switching from one border to another e.g. the left border to the top border. It supports elliptical border radii for when elliptical border radii are added. A ref test is also included. r? @Ms2ger <!-- Reviewable:start --> [<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/7370) <!-- Reviewable:end -->
This commit is contained in:
bors-servo
commit
afc2c381db
4 changed files with 544 additions and 39 deletions
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@ -72,6 +72,19 @@ enum DashSize {
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DashedBorder = 3
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}
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#[derive(Copy, Clone, Debug)]
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struct Ellipse {
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origin: Point2D<f32>,
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width: f32,
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height: f32,
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}
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#[derive(Copy, Clone, Debug)]
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struct Line {
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start: Point2D<f32>,
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end: Point2D<f32>,
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}
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impl<'a> PaintContext<'a> {
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pub fn draw_target(&self) -> &DrawTarget {
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&self.draw_target
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@ -355,6 +368,104 @@ impl<'a> PaintContext<'a> {
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self.draw_target.push_clip(&path_builder.finish());
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}
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fn solve_quadratic(a: f32, b: f32, c: f32) -> (Option<f32>, Option<f32>) {
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let discriminant = b * b - 4. * a * c;
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if discriminant < 0. {
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return (None, None);
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}
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let x1 = (-b + discriminant.sqrt())/(2. * a);
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let x2 = (-b - discriminant.sqrt())/(2. * a);
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if discriminant == 0. {
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return (Some(x1), None);
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}
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return (Some(x1), Some(x2));
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}
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fn intersect_ellipse_line(e: Ellipse, l: Line) -> (Option<Point2D<f32>>, Option<Point2D<f32>>) {
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debug_assert!(l.end.x - l.start.x > f32::EPSILON, "Error line segment end.x > start.x!!");
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// shift the origin to center of the ellipse.
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let line = Line { start: l.start - e.origin,
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end: l.end - e.origin };
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let a = (line.end.y - line.start.y)/(line.end.x - line.start.x);
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let b = line.start.y - (a * line.start.x);
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// given the equation of a line,
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// y = a * x + b,
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// and the equation of an ellipse,
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// x^2/w^2 + y^2/h^2 = 1,
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// substitute y = a * x + b, giving
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// x^2/w^2 + (a^2x^2 + 2abx + b^2)/h^2 = 1
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// then simplify to
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// (h^2 + w^2a^2)x^2 + 2abw^2x + (b^2w^2 - w^2h^2) = 0
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// finally solve for w using the quadratic equation.
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let w = e.width;
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let h = e.height;
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let quad_a = h * h + w * w * a * a;
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let quad_b = 2. * a * b * w * w;
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let quad_c = b * b * w * w - w * w * h * h;
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let intersections = PaintContext::solve_quadratic(quad_a, quad_b, quad_c);
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match intersections {
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(Some(x0), Some(x1)) => {
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let mut p0 = Point2D::new(x0, a * x0 + b) + e.origin;
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let mut p1 = Point2D::new(x1, a * x1 + b) + e.origin;
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if x0 > x1 {
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mem::swap(&mut p0, &mut p1);
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}
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(Some(p0), Some(p1))
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},
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(Some(x0), None) => {
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let p = Point2D::new(x0, a * x0 + b) + e.origin;
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(Some(p), None)
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},
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(None, Some(x1)) => {
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let p = Point2D::new(x1, a * x1 + b) + e.origin;
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(Some(p), None)
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},
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(None, None) => (None, None),
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}
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}
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// Given an ellipse and line segment, the line segment may intersect the
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// ellipse at 0, 1, or 2 points. We compute those intersection points.
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// For each intersection point the angle of the point on the ellipse relative to
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// the top|bottom of the ellipse is computed.
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// Examples:
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// - intersection at ellipse.center + (0, ellipse.height), the angle is 0 rad.
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// - intersection at ellipse.center + (0, -ellipse.height), the angle is 0 rad.
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// - intersection at ellipse.center + (+-ellipse.width, 0), the angle is pi/2.
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fn ellipse_line_intersection_angles(e: Ellipse, l: Line)
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-> (Option<(Point2D<f32>, f32)>, Option<(Point2D<f32>, f32)>) {
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fn point_angle(e: Ellipse, intersect_point: Point2D<f32>) -> f32 {
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((intersect_point.y - e.origin.y).abs() / e.height).asin()
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}
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let intersection = PaintContext::intersect_ellipse_line(e, l);
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match intersection {
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(Some(p0), Some(p1)) => (Some((p0, point_angle(e, p0))), Some((p1, point_angle(e, p1)))),
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(Some(p0), None) => (Some((p0, point_angle(e, p0))), None),
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(None, Some(p1)) => (None, Some((p1, point_angle(e, p1)))),
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(None, None) => (None, None),
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}
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}
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fn ellipse_rightmost_line_intersection_angle(e: Ellipse, l: Line) -> Option<f32> {
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match PaintContext::ellipse_line_intersection_angles(e, l) {
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(Some((p0, angle0)), Some((p1, _))) if p0.x > p1.x => Some(angle0),
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(_, Some((_, angle1))) => Some(angle1),
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(Some((_, angle0)), None) => Some(angle0),
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(None, None) => None,
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}
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}
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fn ellipse_leftmost_line_intersection_angle(e: Ellipse, l: Line) -> Option<f32> {
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match PaintContext::ellipse_line_intersection_angles(e, l) {
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(Some((p0, angle0)), Some((p1, _))) if p0.x < p1.x => Some(angle0),
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(_, Some((_, angle1))) => Some(angle1),
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(Some((_, angle0)), None) => Some(angle0),
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(None, None) => None,
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}
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}
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// The following comment is wonderful, and stolen from
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// gecko:gfx/thebes/gfxContext.cpp:RoundedRectangle for reference.
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//
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@ -450,6 +561,11 @@ impl<'a> PaintContext<'a> {
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let box_BL = box_TL + Point2D::new(0.0, bounds.size.height);
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let box_BR = box_TL + Point2D::new(bounds.size.width, bounds.size.height);
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let inner_TL = box_TL + Point2D::new(border.left, border.top);
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let inner_TR = box_TR + Point2D::new(-border.right, border.top);
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let inner_BR = box_BR + Point2D::new(-border.right, -border.bottom);
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let inner_BL = box_BL + Point2D::new(border.left, -border.bottom);
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let rad_R: AzFloat = 0.;
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let rad_BR = rad_R + f32::consts::FRAC_PI_4;
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let rad_B = rad_BR + f32::consts::FRAC_PI_4;
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@ -457,7 +573,6 @@ impl<'a> PaintContext<'a> {
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let rad_L = rad_BL + f32::consts::FRAC_PI_4;
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let rad_TL = rad_L + f32::consts::FRAC_PI_4;
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let rad_T = rad_TL + f32::consts::FRAC_PI_4;
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let rad_TR = rad_T + f32::consts::FRAC_PI_4;
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fn dx(x: AzFloat) -> Point2D<AzFloat> {
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Point2D::new(x, 0.)
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@ -475,12 +590,41 @@ impl<'a> PaintContext<'a> {
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Point2D::new(0., if cond { dy } else { 0. })
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}
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fn compatible_borders_corner(border1_width: f32, border2_width: f32) -> bool {
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(border1_width - border2_width).abs() <= f32::EPSILON
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}
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let distance_to_elbow_TL =
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if border.top == border.left {
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(radius.top_left - border.top).max(0.)
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} else {
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0.
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};
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let distance_to_elbow_TR =
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if border.top == border.right {
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(radius.top_right - border.top).max(0.)
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} else {
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0.
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};
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let distance_to_elbow_BR =
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if border.right == border.bottom {
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(radius.bottom_right - border.bottom).max(0.)
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} else {
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0.
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};
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let distance_to_elbow_BL =
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if border.left == border.bottom {
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(radius.bottom_left - border.bottom).max(0.)
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} else {
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0.
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};
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match direction {
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Direction::Top => {
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let edge_TL = box_TL + dx(radius.top_left.max(border.left));
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let edge_TR = box_TR + dx(-radius.top_right.max(border.right));
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let edge_BR = edge_TR + dy(border.top);
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let edge_BL = edge_TL + dy(border.top);
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let edge_BR = box_TR + dx(-border.right - distance_to_elbow_TR) + dy(border.top);
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let edge_BL = box_TL + dx(border.left + distance_to_elbow_TL) + dy(border.top);
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let corner_TL = edge_TL + dx_if(radius.top_left == 0., -border.left);
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let corner_TR = edge_TR + dx_if(radius.top_right == 0., border.right);
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@ -497,11 +641,18 @@ impl<'a> PaintContext<'a> {
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// the origin is the center of the arcs we're about to draw.
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let origin = edge_TR + Point2D::new((border.right - radius.top_right).max(0.),
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radius.top_right);
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// the elbow is the inside of the border's curve.
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let distance_to_elbow = (radius.top_right - border.top).max(0.);
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let angle = if compatible_borders_corner(border.top, border.right) {
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f32::consts::FRAC_PI_4
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} else {
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let line = Line { start: inner_TR, end: box_TR };
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let ellipse = Ellipse { origin: origin, width: radius.top_right, height: radius.top_right };
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PaintContext::ellipse_rightmost_line_intersection_angle(ellipse, line).unwrap()
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};
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path_builder.arc(origin, radius.top_right, rad_T, rad_TR, false);
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path_builder.arc(origin, distance_to_elbow, rad_TR, rad_T, true);
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path_builder.arc(origin, radius.top_right, rad_T, rad_R - angle, false);
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if distance_to_elbow_TR != 0. {
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path_builder.arc(origin, distance_to_elbow_TR, rad_R - angle, rad_T, true);
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}
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}
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match mode {
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@ -514,18 +665,26 @@ impl<'a> PaintContext<'a> {
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if radius.top_left != 0. {
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let origin = edge_TL + Point2D::new(-(border.left - radius.top_left).max(0.),
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radius.top_left);
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let distance_to_elbow = (radius.top_left - border.top).max(0.);
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radius.top_left);
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let angle = if compatible_borders_corner(border.top, border.left) {
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f32::consts::FRAC_PI_4
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} else {
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let line = Line { start: box_TL, end: inner_TL };
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let ellipse = Ellipse { origin: origin, width: radius.top_left, height: radius.top_left };
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PaintContext::ellipse_leftmost_line_intersection_angle(ellipse, line).unwrap()
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};
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path_builder.arc(origin, distance_to_elbow, rad_T, rad_TL, true);
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path_builder.arc(origin, radius.top_left, rad_TL, rad_T, false);
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if distance_to_elbow_TL != 0. {
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path_builder.arc(origin, distance_to_elbow_TL, rad_T, rad_L + angle, true);
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}
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path_builder.arc(origin, radius.top_left, rad_L + angle, rad_T, false);
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}
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}
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Direction::Left => {
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let edge_TL = box_TL + dy(radius.top_left.max(border.top));
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let edge_BL = box_BL + dy(-radius.bottom_left.max(border.bottom));
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let edge_TR = edge_TL + dx(border.left);
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let edge_BR = edge_BL + dx(border.left);
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let edge_TR = box_TL + dx(border.left) + dy(border.top + distance_to_elbow_TL);
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let edge_BR = box_BL + dx(border.left) + dy(-border.bottom - distance_to_elbow_BL);
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let corner_TL = edge_TL + dy_if(radius.top_left == 0., -border.top);
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let corner_BL = edge_BL + dy_if(radius.bottom_left == 0., border.bottom);
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@ -540,11 +699,20 @@ impl<'a> PaintContext<'a> {
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if radius.top_left != 0. {
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let origin = edge_TL + Point2D::new(radius.top_left,
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-(border.top - radius.top_left).max(0.));
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let distance_to_elbow = (radius.top_left - border.left).max(0.);
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-(border.top - radius.top_left).max(0.));
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path_builder.arc(origin, radius.top_left, rad_L, rad_TL, false);
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path_builder.arc(origin, distance_to_elbow, rad_TL, rad_L, true);
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let angle = if compatible_borders_corner(border.top, border.left) {
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f32::consts::FRAC_PI_4
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} else {
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let line = Line { start: box_TL, end: inner_TL };
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let ellipse = Ellipse { origin: origin, width: radius.top_left, height: radius.top_left };
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PaintContext::ellipse_leftmost_line_intersection_angle(ellipse, line).unwrap()
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};
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path_builder.arc(origin, radius.top_left, rad_L, rad_L + angle, false);
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if distance_to_elbow_TL != 0. {
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path_builder.arc(origin, distance_to_elbow_TL, rad_L + angle, rad_L, true);
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}
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}
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match mode {
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@ -558,18 +726,28 @@ impl<'a> PaintContext<'a> {
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if radius.bottom_left != 0. {
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let origin = edge_BL +
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Point2D::new(radius.bottom_left,
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(border.bottom - radius.bottom_left).max(0.));
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let distance_to_elbow = (radius.bottom_left - border.left).max(0.);
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(border.bottom - radius.bottom_left).max(0.));
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let angle = if compatible_borders_corner(border.bottom, border.left) {
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f32::consts::FRAC_PI_4
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} else {
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let line = Line { start: box_BL, end: inner_BL };
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let ellipse = Ellipse { origin: origin,
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width: radius.bottom_left,
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height: radius.bottom_left };
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PaintContext::ellipse_leftmost_line_intersection_angle(ellipse, line).unwrap()
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};
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path_builder.arc(origin, distance_to_elbow, rad_L, rad_BL, true);
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path_builder.arc(origin, radius.bottom_left, rad_BL, rad_L, false);
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if distance_to_elbow_BL != 0. {
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path_builder.arc(origin, distance_to_elbow_BL, rad_L, rad_L - angle, true);
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}
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path_builder.arc(origin, radius.bottom_left, rad_L - angle, rad_L, false);
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}
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}
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Direction::Right => {
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let edge_TR = box_TR + dy(radius.top_right.max(border.top));
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let edge_BR = box_BR + dy(-radius.bottom_right.max(border.bottom));
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let edge_TL = edge_TR + dx(-border.right);
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let edge_BL = edge_BR + dx(-border.right);
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let edge_TL = box_TR + dx(-border.right) + dy(border.top + distance_to_elbow_TR);
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let edge_BL = box_BR + dx(-border.right) + dy(-border.bottom - distance_to_elbow_BR);
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let corner_TR = edge_TR + dy_if(radius.top_right == 0., -border.top);
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let corner_BR = edge_BR + dy_if(radius.bottom_right == 0., border.bottom);
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@ -585,10 +763,18 @@ impl<'a> PaintContext<'a> {
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if radius.top_right != 0. {
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let origin = edge_TR + Point2D::new(-radius.top_right,
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-(border.top - radius.top_right).max(0.));
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let distance_to_elbow = (radius.top_right - border.right).max(0.);
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let angle = if compatible_borders_corner(border.top, border.right) {
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f32::consts::FRAC_PI_4
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} else {
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let line = Line { start: inner_TR, end: box_TR };
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let ellipse = Ellipse { origin: origin, width: radius.top_right, height: radius.top_right };
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PaintContext::ellipse_rightmost_line_intersection_angle(ellipse, line).unwrap()
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};
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path_builder.arc(origin, distance_to_elbow, rad_R, rad_TR, true);
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path_builder.arc(origin, radius.top_right, rad_TR, rad_R, false);
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if distance_to_elbow_TR != 0. {
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path_builder.arc(origin, distance_to_elbow_TR, rad_R, rad_R - angle, true);
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}
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path_builder.arc(origin, radius.top_right, rad_R - angle, rad_R, false);
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}
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match mode {
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@ -602,18 +788,28 @@ impl<'a> PaintContext<'a> {
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if radius.bottom_right != 0. {
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let origin = edge_BR +
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Point2D::new(-radius.bottom_right,
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(border.bottom - radius.bottom_right).max(0.));
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let distance_to_elbow = (radius.bottom_right - border.right).max(0.);
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(border.bottom - radius.bottom_right).max(0.));
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let angle = if compatible_borders_corner(border.bottom, border.right) {
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f32::consts::FRAC_PI_4
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} else {
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let line = Line { start: inner_BR, end: box_BR };
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let ellipse = Ellipse { origin: origin,
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width: radius.bottom_right,
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height: radius.bottom_right };
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PaintContext::ellipse_rightmost_line_intersection_angle(ellipse, line).unwrap()
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};
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path_builder.arc(origin, radius.bottom_right, rad_R, rad_BR, false);
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path_builder.arc(origin, distance_to_elbow, rad_BR, rad_R, true);
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path_builder.arc(origin, radius.bottom_right, rad_R, rad_R + angle, false);
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if distance_to_elbow_BR != 0. {
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path_builder.arc(origin, distance_to_elbow_BR, rad_R + angle, rad_R, true);
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}
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}
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}
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Direction::Bottom => {
|
||||
let edge_BL = box_BL + dx(radius.bottom_left.max(border.left));
|
||||
let edge_BR = box_BR + dx(-radius.bottom_right.max(border.right));
|
||||
let edge_TL = edge_BL + dy(-border.bottom);
|
||||
let edge_TR = edge_BR + dy(-border.bottom);
|
||||
let edge_TL = box_BL + dy(-border.bottom) + dx(border.left + distance_to_elbow_BL);
|
||||
let edge_TR = box_BR + dy(-border.bottom) + dx(-border.right - distance_to_elbow_BR);
|
||||
|
||||
let corner_BR = edge_BR + dx_if(radius.bottom_right == 0., border.right);
|
||||
let corner_BL = edge_BL + dx_if(radius.bottom_left == 0., -border.left);
|
||||
|
|
@ -629,10 +825,20 @@ impl<'a> PaintContext<'a> {
|
|||
if radius.bottom_right != 0. {
|
||||
let origin = edge_BR + Point2D::new((border.right - radius.bottom_right).max(0.),
|
||||
-radius.bottom_right);
|
||||
let distance_to_elbow = (radius.bottom_right - border.bottom).max(0.);
|
||||
let angle = if compatible_borders_corner(border.bottom, border.right) {
|
||||
f32::consts::FRAC_PI_4
|
||||
} else {
|
||||
let line = Line { start: inner_BR, end: box_BR };
|
||||
let ellipse = Ellipse { origin: origin,
|
||||
width: radius.bottom_right,
|
||||
height: radius.bottom_right };
|
||||
PaintContext::ellipse_rightmost_line_intersection_angle(ellipse, line).unwrap()
|
||||
};
|
||||
|
||||
path_builder.arc(origin, distance_to_elbow, rad_B, rad_BR, true);
|
||||
path_builder.arc(origin, radius.bottom_right, rad_BR, rad_B, false);
|
||||
if distance_to_elbow_BR != 0. {
|
||||
path_builder.arc(origin, distance_to_elbow_BR, rad_B, rad_R + angle, true);
|
||||
}
|
||||
path_builder.arc(origin, radius.bottom_right, rad_R + angle, rad_B, false);
|
||||
}
|
||||
|
||||
match mode {
|
||||
|
|
@ -645,11 +851,21 @@ impl<'a> PaintContext<'a> {
|
|||
|
||||
if radius.bottom_left != 0. {
|
||||
let origin = edge_BL - Point2D::new((border.left - radius.bottom_left).max(0.),
|
||||
radius.bottom_left);
|
||||
let distance_to_elbow = (radius.bottom_left - border.bottom).max(0.);
|
||||
radius.bottom_left);
|
||||
let angle = if compatible_borders_corner(border.bottom, border.left) {
|
||||
f32::consts::FRAC_PI_4
|
||||
} else {
|
||||
let line = Line { start: box_BL, end: inner_BL };
|
||||
let ellipse = Ellipse { origin: origin,
|
||||
width: radius.bottom_left,
|
||||
height: radius.bottom_left };
|
||||
PaintContext::ellipse_leftmost_line_intersection_angle(ellipse, line).unwrap()
|
||||
};
|
||||
|
||||
path_builder.arc(origin, radius.bottom_left, rad_B, rad_BL, false);
|
||||
path_builder.arc(origin, distance_to_elbow, rad_BL, rad_B, true);
|
||||
path_builder.arc(origin, radius.bottom_left, rad_B, rad_L - angle, false);
|
||||
if distance_to_elbow_BL != 0. {
|
||||
path_builder.arc(origin, distance_to_elbow_BL, rad_L - angle, rad_B, true);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue