ladybird/Userland/Libraries/LibWeb/Painting/BorderPainting.cpp
Andreas Kling 655d9d1462 LibWeb: Make CSSPixels and Length use 64-bit (double) floating point
This fixes a plethora of rounding problems on many websites.
In the future, we may want to replace this with fixed-point arithmetic
(bug #18566) for performance (and consistency with other engines),
but in the meantime this makes the web look a bit better. :^)

There's a lot more things that could be converted to doubles, which
would reduce the amount of casting necessary in this patch.
We can do that incrementally, however.
2023-05-24 14:40:35 +02:00

378 lines
19 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021-2022, Sam Atkins <atkinssj@serenityos.org>
* Copyright (c) 2022, MacDue <macdue@dueutil.tech>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibGfx/AntiAliasingPainter.h>
#include <LibGfx/Painter.h>
#include <LibGfx/Path.h>
#include <LibWeb/Painting/BorderPainting.h>
#include <LibWeb/Painting/PaintContext.h>
namespace Web::Painting {
BorderRadiiData normalized_border_radii_data(Layout::Node const& node, CSSPixelRect const& rect, CSS::BorderRadiusData top_left_radius, CSS::BorderRadiusData top_right_radius, CSS::BorderRadiusData bottom_right_radius, CSS::BorderRadiusData bottom_left_radius)
{
BorderRadiusData bottom_left_radius_px {};
BorderRadiusData bottom_right_radius_px {};
BorderRadiusData top_left_radius_px {};
BorderRadiusData top_right_radius_px {};
bottom_left_radius_px.horizontal_radius = bottom_left_radius.horizontal_radius.to_px(node, rect.width());
bottom_right_radius_px.horizontal_radius = bottom_right_radius.horizontal_radius.to_px(node, rect.width());
top_left_radius_px.horizontal_radius = top_left_radius.horizontal_radius.to_px(node, rect.width());
top_right_radius_px.horizontal_radius = top_right_radius.horizontal_radius.to_px(node, rect.width());
bottom_left_radius_px.vertical_radius = bottom_left_radius.vertical_radius.to_px(node, rect.height());
bottom_right_radius_px.vertical_radius = bottom_right_radius.vertical_radius.to_px(node, rect.height());
top_left_radius_px.vertical_radius = top_left_radius.vertical_radius.to_px(node, rect.height());
top_right_radius_px.vertical_radius = top_right_radius.vertical_radius.to_px(node, rect.height());
// Scale overlapping curves according to https://www.w3.org/TR/css-backgrounds-3/#corner-overlap
CSSPixels f = 1.0f;
auto width_reciprocal = 1.0 / rect.width().value();
auto height_reciprocal = 1.0 / rect.height().value();
f = max(f, width_reciprocal * (top_left_radius_px.horizontal_radius + top_right_radius_px.horizontal_radius));
f = max(f, height_reciprocal * (top_right_radius_px.vertical_radius + bottom_right_radius_px.vertical_radius));
f = max(f, width_reciprocal * (bottom_left_radius_px.horizontal_radius + bottom_right_radius_px.horizontal_radius));
f = max(f, height_reciprocal * (top_left_radius_px.vertical_radius + bottom_left_radius_px.vertical_radius));
f = 1.0 / f.value();
top_left_radius_px.horizontal_radius *= f;
top_left_radius_px.vertical_radius *= f;
top_right_radius_px.horizontal_radius *= f;
top_right_radius_px.vertical_radius *= f;
bottom_right_radius_px.horizontal_radius *= f;
bottom_right_radius_px.vertical_radius *= f;
bottom_left_radius_px.horizontal_radius *= f;
bottom_left_radius_px.vertical_radius *= f;
return BorderRadiiData { top_left_radius_px, top_right_radius_px, bottom_right_radius_px, bottom_left_radius_px };
}
void paint_border(PaintContext& context, BorderEdge edge, DevicePixelRect const& rect, BorderRadiiData const& border_radii_data, BordersData const& borders_data)
{
auto const& border_data = [&] {
switch (edge) {
case BorderEdge::Top:
return borders_data.top;
case BorderEdge::Right:
return borders_data.right;
case BorderEdge::Bottom:
return borders_data.bottom;
default: // BorderEdge::Left:
return borders_data.left;
}
}();
CSSPixels width = border_data.width;
if (width <= 0)
return;
auto color = border_data.color;
auto border_style = border_data.line_style;
auto device_pixel_width = context.enclosing_device_pixels(width);
struct Points {
DevicePixelPoint p1;
DevicePixelPoint p2;
};
auto points_for_edge = [](BorderEdge edge, DevicePixelRect const& rect) -> Points {
switch (edge) {
case BorderEdge::Top:
return { rect.top_left(), rect.top_right().moved_left(1) };
case BorderEdge::Right:
return { rect.top_right().moved_left(1), rect.bottom_right().translated(-1) };
case BorderEdge::Bottom:
return { rect.bottom_left().moved_up(1), rect.bottom_right().translated(-1) };
default: // Edge::Left
return { rect.top_left(), rect.bottom_left().moved_up(1) };
}
};
if (border_style == CSS::LineStyle::Inset) {
auto top_left_color = Color::from_rgb(0x5a5a5a);
auto bottom_right_color = Color::from_rgb(0x888888);
color = (edge == BorderEdge::Left || edge == BorderEdge::Top) ? top_left_color : bottom_right_color;
} else if (border_style == CSS::LineStyle::Outset) {
auto top_left_color = Color::from_rgb(0x888888);
auto bottom_right_color = Color::from_rgb(0x5a5a5a);
color = (edge == BorderEdge::Left || edge == BorderEdge::Top) ? top_left_color : bottom_right_color;
}
auto gfx_line_style = Gfx::Painter::LineStyle::Solid;
if (border_style == CSS::LineStyle::Dotted)
gfx_line_style = Gfx::Painter::LineStyle::Dotted;
if (border_style == CSS::LineStyle::Dashed)
gfx_line_style = Gfx::Painter::LineStyle::Dashed;
if (gfx_line_style != Gfx::Painter::LineStyle::Solid) {
auto [p1, p2] = points_for_edge(edge, rect);
switch (edge) {
case BorderEdge::Top:
p1.translate_by(device_pixel_width / 2, device_pixel_width / 2);
p2.translate_by(-device_pixel_width / 2, device_pixel_width / 2);
break;
case BorderEdge::Right:
p1.translate_by(-device_pixel_width / 2, device_pixel_width / 2);
p2.translate_by(-device_pixel_width / 2, -device_pixel_width / 2);
break;
case BorderEdge::Bottom:
p1.translate_by(device_pixel_width / 2, -device_pixel_width / 2);
p2.translate_by(-device_pixel_width / 2, -device_pixel_width / 2);
break;
case BorderEdge::Left:
p1.translate_by(device_pixel_width / 2, device_pixel_width / 2);
p2.translate_by(device_pixel_width / 2, -device_pixel_width / 2);
break;
}
if (border_style == CSS::LineStyle::Dotted) {
Gfx::AntiAliasingPainter aa_painter { context.painter() };
aa_painter.draw_line(p1.to_type<int>(), p2.to_type<int>(), color, device_pixel_width.value(), gfx_line_style);
return;
}
context.painter().draw_line(p1.to_type<int>(), p2.to_type<int>(), color, device_pixel_width.value(), gfx_line_style);
return;
}
auto draw_horizontal_or_vertical_line = [&](auto p1, auto p2) {
// Note: Using fill_rect() here since draw_line() produces some overlapping pixels
// at the end of a line, which cause issues on borders with transparency.
p2.translate_by(1, 1);
context.painter().fill_rect(Gfx::IntRect::from_two_points(p1.template to_type<int>(), p2.template to_type<int>()), color);
};
auto draw_border = [&](auto const& border, auto const& radius, auto const& opposite_border, auto const& opposite_radius, auto p1_step_translate, auto p2_step_translate) {
auto [p1, p2] = points_for_edge(edge, rect);
auto p1_step = radius ? 0 : border.width / device_pixel_width.value();
auto p2_step = opposite_radius ? 0 : opposite_border.width / device_pixel_width.value();
for (DevicePixels i = 0; i < device_pixel_width; ++i) {
draw_horizontal_or_vertical_line(p1, p2);
p1_step_translate(p1, p1_step);
p2_step_translate(p2, p2_step);
}
};
// FIXME: There is some overlap where two borders (without border radii meet),
// which produces artifacts if the border color has some transparency.
// (this only happens if the angle between the two borders is not 45 degrees)
switch (edge) {
case BorderEdge::Top:
draw_border(
borders_data.left, border_radii_data.top_left, borders_data.right, border_radii_data.top_right,
[](auto& current_p1, auto step) {
current_p1.translate_by(step, 1);
},
[](auto& current_p2, auto step) {
current_p2.translate_by(-step, 1);
});
break;
case BorderEdge::Right:
draw_border(
borders_data.top, border_radii_data.top_right, borders_data.bottom, border_radii_data.bottom_right,
[](auto& current_p1, auto step) {
current_p1.translate_by(-1, step);
},
[](auto& current_p2, auto step) {
current_p2.translate_by(-1, -step);
});
break;
case BorderEdge::Bottom:
draw_border(
borders_data.left, border_radii_data.bottom_left, borders_data.right, border_radii_data.bottom_right,
[](auto& current_p1, auto step) {
current_p1.translate_by(step, -1);
},
[](auto& current_p2, auto step) {
current_p2.translate_by(-step, -1);
});
break;
case BorderEdge::Left:
draw_border(
borders_data.top, border_radii_data.top_left, borders_data.bottom, border_radii_data.bottom_left,
[](auto& current_p1, auto step) {
current_p1.translate_by(1, step);
},
[](auto& current_p2, auto step) {
current_p2.translate_by(1, -step);
});
break;
}
}
RefPtr<Gfx::Bitmap> get_cached_corner_bitmap(DevicePixelSize corners_size)
{
auto allocate_mask_bitmap = [&]() -> RefPtr<Gfx::Bitmap> {
auto bitmap = Gfx::Bitmap::create(Gfx::BitmapFormat::BGRA8888, corners_size.to_type<int>());
if (!bitmap.is_error())
return bitmap.release_value();
return nullptr;
};
// FIXME: Allocate per page?
static thread_local auto corner_bitmap = allocate_mask_bitmap();
// Only reallocate the corner bitmap is the existing one is too small.
// (should mean no more allocations after the first paint -- amortised zero allocations :^))
if (corner_bitmap && corner_bitmap->rect().size().contains(corners_size.to_type<int>())) {
Gfx::Painter painter { *corner_bitmap };
painter.clear_rect({ { 0, 0 }, corners_size }, Gfx::Color());
} else {
corner_bitmap = allocate_mask_bitmap();
if (!corner_bitmap) {
dbgln("Failed to allocate corner bitmap with size {}", corners_size);
return nullptr;
}
}
return corner_bitmap;
}
void paint_all_borders(PaintContext& context, CSSPixelRect const& bordered_rect, BorderRadiiData const& border_radii_data, BordersData const& borders_data)
{
if (borders_data.top.width <= 0 && borders_data.right.width <= 0 && borders_data.left.width <= 0 && borders_data.bottom.width <= 0)
return;
auto border_rect = context.rounded_device_rect(bordered_rect);
auto top_left = border_radii_data.top_left.as_corner(context);
auto top_right = border_radii_data.top_right.as_corner(context);
auto bottom_right = border_radii_data.bottom_right.as_corner(context);
auto bottom_left = border_radii_data.bottom_left.as_corner(context);
// Disable border radii if the corresponding borders don't exist:
if (borders_data.bottom.width <= 0 && borders_data.left.width <= 0)
bottom_left = { 0, 0 };
if (borders_data.bottom.width <= 0 && borders_data.right.width <= 0)
bottom_right = { 0, 0 };
if (borders_data.top.width <= 0 && borders_data.left.width <= 0)
top_left = { 0, 0 };
if (borders_data.top.width <= 0 && borders_data.right.width <= 0)
top_right = { 0, 0 };
DevicePixelRect top_border_rect = {
border_rect.x() + top_left.horizontal_radius,
border_rect.y(),
border_rect.width() - top_left.horizontal_radius - top_right.horizontal_radius,
context.enclosing_device_pixels(borders_data.top.width)
};
DevicePixelRect right_border_rect = {
border_rect.x() + (border_rect.width() - context.enclosing_device_pixels(borders_data.right.width)),
border_rect.y() + top_right.vertical_radius,
context.enclosing_device_pixels(borders_data.right.width),
border_rect.height() - top_right.vertical_radius - bottom_right.vertical_radius
};
DevicePixelRect bottom_border_rect = {
border_rect.x() + bottom_left.horizontal_radius,
border_rect.y() + (border_rect.height() - context.enclosing_device_pixels(borders_data.bottom.width)),
border_rect.width() - bottom_left.horizontal_radius - bottom_right.horizontal_radius,
context.enclosing_device_pixels(borders_data.bottom.width)
};
DevicePixelRect left_border_rect = {
border_rect.x(),
border_rect.y() + top_left.vertical_radius,
context.enclosing_device_pixels(borders_data.left.width),
border_rect.height() - top_left.vertical_radius - bottom_left.vertical_radius
};
// Avoid overlapping pixels on the edges, in the easy 45 degree corners case:
if (!top_left && top_border_rect.height() == left_border_rect.width())
top_border_rect.shrink(0, 0, 0, 1);
if (!top_right && top_border_rect.height() == right_border_rect.width())
top_border_rect.shrink(0, 1, 0, 0);
if (!bottom_left && bottom_border_rect.height() == left_border_rect.width())
bottom_border_rect.shrink(0, 0, 0, 1);
if (!bottom_right && bottom_border_rect.height() == right_border_rect.width())
bottom_border_rect.shrink(0, 1, 0, 0);
auto border_color_no_alpha = borders_data.top.color;
border_color_no_alpha.set_alpha(255);
// Paint the strait line part of the border:
paint_border(context, BorderEdge::Top, top_border_rect, border_radii_data, borders_data);
paint_border(context, BorderEdge::Right, right_border_rect, border_radii_data, borders_data);
paint_border(context, BorderEdge::Bottom, bottom_border_rect, border_radii_data, borders_data);
paint_border(context, BorderEdge::Left, left_border_rect, border_radii_data, borders_data);
if (!top_left && !top_right && !bottom_left && !bottom_right)
return;
// Cache the smallest possible bitmap to render just the corners for the border.
auto expand_width = abs(context.enclosing_device_pixels(borders_data.left.width) - context.enclosing_device_pixels(borders_data.right.width));
auto expand_height = abs(context.enclosing_device_pixels(borders_data.top.width) - context.enclosing_device_pixels(borders_data.bottom.width));
DevicePixelRect corner_mask_rect {
0, 0,
max(
top_left.horizontal_radius + top_right.horizontal_radius + expand_width.value(),
bottom_left.horizontal_radius + bottom_right.horizontal_radius + expand_height.value()),
max(
top_left.vertical_radius + bottom_left.vertical_radius + expand_width.value(),
top_right.vertical_radius + bottom_right.vertical_radius + expand_height.value())
};
auto corner_bitmap = get_cached_corner_bitmap(corner_mask_rect.size());
if (!corner_bitmap)
return;
Gfx::Painter painter { *corner_bitmap };
Gfx::AntiAliasingPainter aa_painter { painter };
// Paint a little tile sheet for the corners
// TODO: Support various line styles on the corners (dotted, dashes, etc)
// Paint the outer (minimal) corner rounded rectangle:
aa_painter.fill_rect_with_rounded_corners(corner_mask_rect.to_type<int>(), border_color_no_alpha, top_left, top_right, bottom_right, bottom_left);
// Subtract the inner corner rectangle:
auto inner_corner_mask_rect = corner_mask_rect.shrunken(
context.enclosing_device_pixels(borders_data.top.width),
context.enclosing_device_pixels(borders_data.right.width),
context.enclosing_device_pixels(borders_data.bottom.width),
context.enclosing_device_pixels(borders_data.left.width));
auto inner_top_left = top_left;
auto inner_top_right = top_right;
auto inner_bottom_right = bottom_right;
auto inner_bottom_left = bottom_left;
inner_top_left.horizontal_radius = max(0, inner_top_left.horizontal_radius - context.enclosing_device_pixels(borders_data.left.width).value());
inner_top_left.vertical_radius = max(0, inner_top_left.vertical_radius - context.enclosing_device_pixels(borders_data.top.width).value());
inner_top_right.horizontal_radius = max(0, inner_top_right.horizontal_radius - context.enclosing_device_pixels(borders_data.right.width).value());
inner_top_right.vertical_radius = max(0, inner_top_right.vertical_radius - context.enclosing_device_pixels(borders_data.top.width).value());
inner_bottom_right.horizontal_radius = max(0, inner_bottom_right.horizontal_radius - context.enclosing_device_pixels(borders_data.right.width).value());
inner_bottom_right.vertical_radius = max(0, inner_bottom_right.vertical_radius - context.enclosing_device_pixels(borders_data.bottom.width).value());
inner_bottom_left.horizontal_radius = max(0, inner_bottom_left.horizontal_radius - context.enclosing_device_pixels(borders_data.left.width).value());
inner_bottom_left.vertical_radius = max(0, inner_bottom_left.vertical_radius - context.enclosing_device_pixels(borders_data.bottom.width).value());
aa_painter.fill_rect_with_rounded_corners(inner_corner_mask_rect.to_type<int>(), border_color_no_alpha, inner_top_left, inner_top_right, inner_bottom_right, inner_bottom_left, Gfx::AntiAliasingPainter::BlendMode::AlphaSubtract);
// TODO: Support dual color corners. Other browsers will render a rounded corner between two borders of
// different colors using both colours, normally split at a 45 degree angle (though the exact angle is interpolated).
auto blit_corner = [&](Gfx::IntPoint position, Gfx::IntRect const& src_rect, Color corner_color) {
context.painter().blit_filtered(position, *corner_bitmap, src_rect, [&](auto const& corner_pixel) {
return corner_color.with_alpha((corner_color.alpha() * corner_pixel.alpha()) / 255);
});
};
// FIXME: Corners should actually split between the two colors, if both are provided (and differ)
auto pick_corner_color = [](auto const& border, auto const& adjacent_border) {
if (border.width > 0)
return border.color;
return adjacent_border.color;
};
// Blit the corners into to their corresponding locations:
if (top_left)
blit_corner(border_rect.top_left().to_type<int>(), top_left.as_rect(), pick_corner_color(borders_data.top, borders_data.left));
if (top_right)
blit_corner(border_rect.top_right().to_type<int>().translated(-top_right.horizontal_radius, 0), top_right.as_rect().translated(corner_mask_rect.width().value() - top_right.horizontal_radius, 0), pick_corner_color(borders_data.top, borders_data.right));
if (bottom_right)
blit_corner(border_rect.bottom_right().to_type<int>().translated(-bottom_right.horizontal_radius, -bottom_right.vertical_radius), bottom_right.as_rect().translated(corner_mask_rect.width().value() - bottom_right.horizontal_radius, corner_mask_rect.height().value() - bottom_right.vertical_radius), pick_corner_color(borders_data.bottom, borders_data.right));
if (bottom_left)
blit_corner(border_rect.bottom_left().to_type<int>().translated(0, -bottom_left.vertical_radius), bottom_left.as_rect().translated(0, corner_mask_rect.height().value() - bottom_left.vertical_radius), pick_corner_color(borders_data.bottom, borders_data.left));
}
}