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Switch to basic canvas operations to fix circle stroke position #1059

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Switch to basic canvas operations to fix circle stroke position #1059

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0ddf3d9
Moved over to basic canvas rendering for circles to fix stroke position.
orangemug Dec 13, 2023
e1a77a2
Merge remote-tracking branch 'upstream/main' into feature/switch-to-c…
orangemug Dec 13, 2023
e392ac8
Added translate back into circle cache key.
orangemug Dec 13, 2023
40c8a4f
Merge remote-tracking branch 'upstream/main' into feature/switch-to-c…
orangemug Dec 18, 2023
d2aba6d
Fixes for circle-blur and added `setHitDetectionRenderer`
orangemug Dec 18, 2023
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132 changes: 107 additions & 25 deletions src/stylefunction.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,6 @@ Copyright 2016-present ol-mapbox-style contributors
License: https://raw.githubusercontent.com/openlayers/ol-mapbox-style/master/LICENSE
*/

import Circle from 'ol/style/Circle.js';
import Fill from 'ol/style/Fill.js';
import Icon from 'ol/style/Icon.js';
import RenderFeature from 'ol/render/Feature.js';
Expand Down Expand Up @@ -1152,6 +1151,16 @@ export function stylefunction(
functionCache,
featureState
);

const circleBlur = getValue(
layer,
'paint',
'circle-blur',
zoom,
f,
functionCache,
featureState
);
const cache_key =
circleRadius +
'.' +
Expand All @@ -1163,35 +1172,108 @@ export function stylefunction(
'.' +
circleTranslate[0] +
'.' +
circleTranslate[1];
circleTranslate[1] +
'.' +
circleBlur;

const hit_cache_key = cache_key + '_hit';

const renderHitDetection = (
[x, y],
renderOpts,
pixelRatioOverride
) => {
// NOTE: Hit detection rendering appears to assume pixelRatio of 1
// Allowing an `pixelRatioOverride` allows us debug by using this
// function in `setRenderer`
const pixelRatio = pixelRatioOverride || 1;
const r =
circleRadius * pixelRatio +
circleStrokeWidth * pixelRatio +
circleBlur * pixelRatio;
const sw = circleStrokeWidth * pixelRatio;
const cb = circleBlur * pixelRatio;
const xo = x + circleTranslate[0] * pixelRatio;
const yo = y + circleTranslate[1] * pixelRatio;

const w = r * 2 + sw * 2 + cb * 3 + 1;
const h = r * 2 + sw * 2 + cb * 3 + 1;

let bitmap = iconImageCache[hit_cache_key];
if (!bitmap) {
const offscreenBuffer = new OffscreenCanvas(w, h);
const ctx = offscreenBuffer.getContext('2d');

const ox = w / 2;
const oy = h / 2;

ctx.save();
ctx.beginPath();
ctx.arc(ox, oy, r, 0, 2 * Math.PI);
ctx.fillStyle = 'black';
ctx.fill();
ctx.closePath();
ctx.restore();

bitmap = offscreenBuffer.transferToImageBitmap();
iconImageCache[hit_cache_key] = bitmap;
}
renderOpts.context.drawImage(bitmap, xo - w / 2, yo - h / 2);
};

const styleRender = ([x, y], renderOpts) => {
const r = circleRadius * renderOpts.pixelRatio;
const sw = circleStrokeWidth * renderOpts.pixelRatio;
const cb = circleBlur * renderOpts.pixelRatio;
const xo = x + circleTranslate[0] * renderOpts.pixelRatio;
const yo = y + circleTranslate[1] * renderOpts.pixelRatio;

const w = r * 2 + sw * 2 + cb * 4 + 1;
const h = r * 2 + sw * 2 + cb * 4 + 1;

let bitmap = iconImageCache[cache_key];
if (!bitmap) {
const offscreenBuffer = new OffscreenCanvas(w, h);
const ctx = offscreenBuffer.getContext('2d');

if (cb !== 0) {
ctx.filter = `blur(${cb}px)`;
}

const ox = w / 2;
const oy = h / 2;

ctx.save();
ctx.beginPath();
ctx.arc(ox, oy, r, 0, 2 * Math.PI);
ctx.fillStyle = 'pink';
ctx.fill();
ctx.closePath();
ctx.restore();

if (circleStrokeWidth > 0) {
ctx.save();
ctx.beginPath();
ctx.arc(ox, oy, r + sw / 2, 0, 2 * Math.PI);
ctx.strokeStyle = circleStrokeColor;
ctx.lineWidth = sw;
ctx.stroke();
ctx.closePath();
ctx.restore();
ctx.restore();
}
bitmap = offscreenBuffer.transferToImageBitmap();
iconImageCache[cache_key] = bitmap;
}
renderOpts.context.drawImage(bitmap, xo - w / 2, yo - h / 2);
};

iconImg = iconImageCache[cache_key];
if (!iconImg) {
iconImg = new Circle({
radius: circleRadius,
displacement: [circleTranslate[0], -circleTranslate[1]],
stroke:
circleStrokeColor && circleStrokeWidth > 0
? new Stroke({
width: circleStrokeWidth,
color: circleStrokeColor,
})
: undefined,
fill: circleColor
? new Fill({
color: circleColor,
})
: undefined,
declutterMode: 'none',
});
iconImageCache[cache_key] = iconImg;
}
style.setImage(iconImg);
text = style.getText();
style.setText(undefined);
style.setGeometry(undefined);
style.setZIndex(index);
hasImage = true;
style.setHitDetectionRenderer(renderHitDetection);
style.setRenderer(styleRender);
}

let label, font, textLineHeight, textSize, letterSpacing, maxTextWidth;
Expand Down