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[emath] RectTransform: transforms Pos2 from one Rect to another

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Very useful for transforming coordinate systems, e.g. for painting
This commit is contained in:
Emil Ernerfeldt
2021-02-14 10:33:44 +01:00
parent dbc6a620cd
commit c376d0bb7e
8 changed files with 142 additions and 24 deletions
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9
egui_demo_lib/src/apps/demo/dancing_strings.rs
View File

@@ -34,6 +34,9 @@ impl super::View for DancingStrings {
let desired_size = ui.available_width() * vec2(1.0, 0.35);
let (_id, rect) = ui.allocate_space(desired_size);
let to_screen =
math::RectTransform::from_to(Rect::from_x_y_ranges(0.0..=1.0, -1.0..=1.0), rect);
let mut shapes = vec![];
for &mode in &[2, 3, 5] {
@@ -46,11 +49,7 @@ impl super::View for DancingStrings {
let t = i as f32 / (n as f32);
let amp = (time as f32 * speed * mode).sin() / mode;
let y = amp * (t * std::f32::consts::TAU / 2.0 * mode).sin();
pos2(
lerp(rect.x_range(), t),
remap(y, -1.0..=1.0, rect.y_range()),
)
to_screen * pos2(t, y)
})
.collect();

13
egui_demo_lib/src/apps/demo/painting.rs
View File

@@ -3,7 +3,8 @@ use egui::*;
#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "persistence", serde(default))]
pub struct Painting {
lines: Vec<Vec<Vec2>>,
/// in 0-1 normalized coordinates
lines: Vec<Vec<Pos2>>,
stroke: Stroke,
}
@@ -32,6 +33,12 @@ impl Painting {
ui.allocate_painter(ui.available_size_before_wrap_finite(), Sense::drag());
let rect = response.rect;
let to_screen = emath::RectTransform::from_to(
Rect::from_min_size(Pos2::ZERO, rect.square_proportions()),
rect,
);
let from_screen = to_screen.inverse();
if self.lines.is_empty() {
self.lines.push(vec![]);
}
@@ -39,7 +46,7 @@ impl Painting {
let current_line = self.lines.last_mut().unwrap();
if let Some(pointer_pos) = response.interact_pointer_pos() {
let canvas_pos = pointer_pos - rect.min;
let canvas_pos = from_screen * pointer_pos;
if current_line.last() != Some(&canvas_pos) {
current_line.push(canvas_pos);
}
@@ -49,7 +56,7 @@ impl Painting {
for line in &self.lines {
if line.len() >= 2 {
let points: Vec<Pos2> = line.iter().map(|p| rect.min + *p).collect();
let points: Vec<Pos2> = line.iter().map(|p| to_screen * *p).collect();
painter.add(Shape::line(points, self.stroke));
}
}

21
egui_demo_lib/src/apps/fractal_clock.rs
View File

@@ -100,8 +100,6 @@ impl FractalClock {
}
fn paint(&mut self, painter: &Painter) {
let rect = painter.clip_rect();
struct Hand {
length: f32,
angle: f32,
@@ -130,14 +128,18 @@ impl FractalClock {
Hand::from_length_angle(0.5, angle_from_period(12.0 * 60.0 * 60.0)),
];
let scale = self.zoom * rect.width().min(rect.height());
let mut shapes: Vec<Shape> = Vec::new();
let mut paint_line = |points: [Pos2; 2], color: Color32, width: f32| {
let line = [
rect.center() + scale * points[0].to_vec2(),
rect.center() + scale * points[1].to_vec2(),
];
let rect = painter.clip_rect();
let to_screen = emath::RectTransform::from_to(
Rect::from_center_size(Pos2::ZERO, rect.square_proportions() / self.zoom),
rect,
);
let mut paint_line = |points: [Pos2; 2], color: Color32, width: f32| {
let line = [to_screen * points[0], to_screen * points[1]];
// culling
if rect.intersects(Rect::from_two_pos(line[0], line[1])) {
shapes.push(Shape::line_segment(line, (width, color)));
}
@@ -186,6 +188,9 @@ impl FractalClock {
width *= self.width_factor;
let luminance_u8 = (255.0 * luminance).round() as u8;
if luminance_u8 == 0 {
break;
}
for &rotor in &hand_rotors {
for a in &nodes {

19
egui_demo_lib/src/frame_history.rs
View File

@@ -58,7 +58,6 @@ impl FrameHistory {
fn graph(&mut self, ui: &mut egui::Ui) -> egui::Response {
use egui::*;
let graph_top_cpu_usage = 0.010;
ui.label("egui CPU usage history");
let history = &self.frame_times;
@@ -69,12 +68,17 @@ impl FrameHistory {
let (rect, response) = ui.allocate_at_least(size, Sense::hover());
let style = ui.style().noninteractive();
let mut shapes = vec![Shape::Rect {
let graph_top_cpu_usage = 0.010;
let graph_rect = Rect::from_x_y_ranges(history.max_age()..=0.0, graph_top_cpu_usage..=0.0);
let to_screen = emath::RectTransform::from_to(graph_rect, rect);
let mut shapes = Vec::with_capacity(3 + 2 * history.len());
shapes.push(Shape::Rect {
rect,
corner_radius: style.corner_radius,
fill: ui.visuals().extreme_bg_color,
stroke: ui.style().noninteractive().bg_stroke,
}];
});
let rect = rect.shrink(4.0);
let color = ui.visuals().text_color();
@@ -87,7 +91,7 @@ impl FrameHistory {
[pos2(rect.left(), y), pos2(rect.right(), y)],
line_stroke,
));
let cpu_usage = remap(y, rect.bottom_up_range(), 0.0..=graph_top_cpu_usage);
let cpu_usage = to_screen.inverse().transform_pos(pointer_pos).y;
let text = format!("{:.1} ms", 1e3 * cpu_usage);
shapes.push(Shape::text(
ui.fonts(),
@@ -106,16 +110,15 @@ impl FrameHistory {
for (time, cpu_usage) in history.iter() {
let age = (right_side_time - time) as f32;
let x = remap(age, history.max_age()..=0.0, rect.x_range());
let y = remap_clamp(cpu_usage, 0.0..=graph_top_cpu_usage, rect.bottom_up_range());
let pos = to_screen.transform_pos_clamped(Pos2::new(age, cpu_usage));
shapes.push(Shape::line_segment(
[pos2(x, rect.bottom()), pos2(x, y)],
[pos2(pos.x, rect.bottom()), pos],
line_stroke,
));
if cpu_usage < graph_top_cpu_usage {
shapes.push(Shape::circle_filled(pos2(x, y), radius, circle_color));
shapes.push(Shape::circle_filled(pos, radius, circle_color));
}
}