Handle intersections between two bezier curves (#735)

* Refactor intersections function

* Implement intersect for quadratic and cubic bezier curves

* Return t value instead of point

* Change project return the t value

* Add error threshold for curve intersection

* Refactor to use if let statements and improve comments

* Refactor intersection helper to return vector, other minor name/text changes

* Rename function

* Minor change

* Minor fixes

* Add missing test tag

* Address comments

* Adjust comment

* Change function call

* Edit comments
This commit is contained in:
Hannah Li
2022-07-29 22:37:24 -04:00
committed by GitHub
parent 18871e5bbf
commit fd434a11ed
5 changed files with 238 additions and 93 deletions
+37 -4
View File
@@ -269,7 +269,8 @@ export default defineComponent({
callback: (canvas: HTMLCanvasElement, bezier: WasmBezierInstance, options: Record<string, number>, mouseLocation?: Point): void => {
if (mouseLocation != null) {
const context = getContextFromCanvas(canvas);
const closestPoint = JSON.parse(bezier.project(mouseLocation.x, mouseLocation.y));
const t = bezier.project(mouseLocation.x, mouseLocation.y);
const closestPoint = JSON.parse(bezier.evaluate(t));
drawLine(context, mouseLocation, closestPoint, COLORS.NON_INTERACTIVE.STROKE_1);
}
},
@@ -376,7 +377,7 @@ export default defineComponent({
},
},
{
name: "Intersect Line Segment",
name: "Intersect (Line Segment)",
callback: (canvas: HTMLCanvasElement, bezier: WasmBezierInstance): void => {
const context = getContextFromCanvas(canvas);
const line = [
@@ -385,12 +386,44 @@ export default defineComponent({
];
const mappedLine = line.map((p) => [p.x, p.y]);
drawLine(context, line[0], line[1], COLORS.NON_INTERACTIVE.STROKE_1);
const intersections: Point[] = bezier.intersect_line_segment(mappedLine).map((p) => JSON.parse(p));
intersections.forEach((p: Point) => {
const intersections: Float64Array = bezier.intersect_line_segment(mappedLine);
intersections.forEach((t: number) => {
const p = JSON.parse(bezier.evaluate(t));
drawPoint(context, p, 3, COLORS.NON_INTERACTIVE.STROKE_2);
});
},
},
{
name: "Intersect (Cubic Segment)",
callback: (canvas: HTMLCanvasElement, bezier: WasmBezierInstance, options: Record<string, number>): void => {
const context = getContextFromCanvas(canvas);
const points = [
{ x: 40, y: 20 },
{ x: 100, y: 40 },
{ x: 40, y: 120 },
{ x: 175, y: 140 },
];
const mappedPoints = points.map((p) => [p.x, p.y]);
drawCurve(context, points, COLORS.NON_INTERACTIVE.STROKE_1, 1);
const intersections: Float64Array = bezier.intersect_cubic_segment(mappedPoints, options.error);
intersections.forEach((t: number) => {
const p = JSON.parse(bezier.evaluate(t));
drawPoint(context, p, 3, COLORS.NON_INTERACTIVE.STROKE_2);
});
},
template: markRaw(SliderExample),
templateOptions: {
sliders: [
{
variable: "error",
min: 0.1,
max: 2,
step: 0.1,
default: 0.5,
},
],
},
},
{
name: "Reduce",
callback: (canvas: HTMLCanvasElement, bezier: WasmBezierInstance): void => {
@@ -59,9 +59,9 @@ export const drawText = (ctx: CanvasRenderingContext2D, text: string, x: number,
ctx.fillText(text, x, y);
};
export const drawCurve = (ctx: CanvasRenderingContext2D, points: Point[], strokeColor = COLORS.INTERACTIVE.STROKE_1): void => {
export const drawCurve = (ctx: CanvasRenderingContext2D, points: Point[], strokeColor = COLORS.INTERACTIVE.STROKE_1, lineWidth = 2): void => {
ctx.strokeStyle = strokeColor;
ctx.lineWidth = 2;
ctx.lineWidth = lineWidth;
ctx.beginPath();
ctx.moveTo(points[0].x, points[0].y);