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select filled elements by clicking inside (#340)

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This commit is contained in:
David Luzar 2020-01-12 20:16:48 +01:00 committed by Christopher Chedeau
parent c67435719f
commit 5887be6eda
1 changed files with 53 additions and 2 deletions
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53
src/element/collision.ts
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@ -50,10 +50,25 @@ export function hitTest(
ty /= t;
});
if (element.backgroundColor !== "transparent") {
return (
a * tx - (px - lineThreshold) >= 0 && b * ty - (py - lineThreshold) >= 0
);
} else {
return Math.hypot(a * tx - px, b * ty - py) < lineThreshold;
}
} else if (element.type === "rectangle") {
const [x1, y1, x2, y2] = getElementAbsoluteCoords(element);
if (element.backgroundColor !== "transparent") {
return (
x > x1 - lineThreshold &&
x < x2 + lineThreshold &&
y > y1 - lineThreshold &&
y < y2 + lineThreshold
);
}
// (x1, y1) --A-- (x2, y1)
// |D |B
// (x1, y2) --C-- (x2, y2)
@ -67,7 +82,7 @@ export function hitTest(
x -= element.x;
y -= element.y;
const [
let [
topX,
topY,
rightX,
@ -78,6 +93,42 @@ export function hitTest(
leftY
] = getDiamondPoints(element);
if (element.backgroundColor !== "transparent") {
// TODO: remove this when we normalize coordinates globally
if (topY > bottomY) [bottomY, topY] = [topY, bottomY];
if (rightX < leftX) [leftX, rightX] = [rightX, leftX];
topY -= lineThreshold;
bottomY += lineThreshold;
leftX -= lineThreshold;
rightX += lineThreshold;
// all deltas should be < 0. Delta > 0 indicates it's on the outside side
// of the line.
//
// (topX, topY)
// D / \ A
// / \
// (leftX, leftY) (rightX, rightY)
// C \ / B
// \ /
// (bottomX, bottomY)
//
// https://stackoverflow.com/a/2752753/927631
return (
// delta from line D
(leftX - topX) * (y - leftY) - (leftX - x) * (topY - leftY) <= 0 &&
// delta from line A
(topX - rightX) * (y - rightY) - (x - rightX) * (topY - rightY) <= 0 &&
// delta from line B
(rightX - bottomX) * (y - bottomY) -
(x - bottomX) * (rightY - bottomY) <=
0 &&
// delta from line C
(bottomX - leftX) * (y - leftY) - (x - leftX) * (bottomY - leftY) <= 0
);
}
return (
distanceBetweenPointAndSegment(x, y, topX, topY, rightX, rightY) <
lineThreshold ||