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| author | Maze Winther <mazewinther@gmail.com> | 2025-09-03 00:02:07 +0200 |
|---|---|---|
| committer | Maze Winther <mazewinther@gmail.com> | 2025-09-03 00:02:07 +0200 |
| commit | 60debe2ce52a73dc554a0daa0a127fc836ca123a (patch) | |
| tree | 9c334f5de4211d0bb7893929ea63c86280679705 /apps/web/src/lib/canvas-gradients.ts | |
| parent | 37d40148087fc7c3497fba31e82bc7c7496bde8d (diff) | |
| parent | 167e2b83dc072f5d80ab0bf0d3f786a993248c70 (diff) | |
| download | opencut-60debe2ce52a73dc554a0daa0a127fc836ca123a.tar.gz | |
Merge branch 'staging'
Diffstat (limited to 'apps/web/src/lib/canvas-gradients.ts')
| -rw-r--r-- | apps/web/src/lib/canvas-gradients.ts | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/apps/web/src/lib/canvas-gradients.ts b/apps/web/src/lib/canvas-gradients.ts new file mode 100644 index 00000000..7d1cdc05 --- /dev/null +++ b/apps/web/src/lib/canvas-gradients.ts @@ -0,0 +1,219 @@ +function splitBackgroundLayers(input: string): string[] { + const layers: string[] = []; + let depth = 0; + let start = 0; + for (let i = 0; i < input.length; i += 1) { + const ch = input[i] as string; + if (ch === "(") depth += 1; + else if (ch === ")") depth -= 1; + else if (ch === "," && depth === 0) { + layers.push(input.slice(start, i).trim()); + start = i + 1; + } + } + layers.push(input.slice(start).trim()); + return layers; +} + +function parseColorStop(stop: string): { color: string; position?: number } { + const s = stop.trim(); + + // Handle functional colors like rgba(), rgb(), hsla(), hsl() + const colorFunctions = ["rgba(", "rgb(", "hsla(", "hsl("]; + let color = ""; + let remaining = ""; + + for (const fn of colorFunctions) { + if (s.startsWith(fn)) { + let depth = 0; + for (let i = 0; i < s.length; i += 1) { + const ch = s[i] as string; + if (ch === "(") depth += 1; + else if (ch === ")") { + depth -= 1; + if (depth === 0) { + color = s.slice(0, i + 1); + remaining = s.slice(i + 1).trim(); + break; + } + } + } + break; + } + } + + if (!color) { + const parts = s.split(/\s+/); + color = parts[0] as string; + remaining = parts.slice(1).join(" "); + } + + // Convert transparent to transparent white for better blending + if (color === "transparent") { + color = "rgba(255, 255, 255, 0)"; + } + + // Parse position if present + let position: number | undefined; + if (remaining) { + const posMatch = remaining.match(/(\d+(?:\.\d+)?)%/); + if (posMatch) { + position = parseFloat(posMatch[1] as string) / 100; + } + } + + return { color, position }; +} + +function parseLinearGradient(layer: string, width: number, height: number) { + const inside = layer.slice(layer.indexOf("(") + 1, layer.lastIndexOf(")")); + const parts = splitBackgroundLayers(inside); + const dir = (parts.shift() || "").trim(); + + let x0 = 0, + y0 = 0, + x1 = width, + y1 = 0; // default: to right + + if (dir.endsWith("deg")) { + const deg = parseFloat(dir); + const rad = (deg * Math.PI) / 180; + const cx = width / 2; + const cy = height / 2; + const r = Math.hypot(width, height) / 2; + x0 = cx - Math.cos(rad) * r; + y0 = cy - Math.sin(rad) * r; + x1 = cx + Math.cos(rad) * r; + y1 = cy + Math.sin(rad) * r; + } else if (dir.startsWith("to ")) { + const d = dir.slice(3).trim(); + if (d === "right") { + x0 = 0; + y0 = 0; + x1 = width; + y1 = 0; + } else if (d === "left") { + x0 = width; + y0 = 0; + x1 = 0; + y1 = 0; + } else if (d === "bottom") { + x0 = 0; + y0 = 0; + x1 = 0; + y1 = height; + } else if (d === "top") { + x0 = 0; + y0 = height; + x1 = 0; + y1 = 0; + } + } else { + // No direction specified, treat as first color + parts.unshift(dir); + } + + return { x0, y0, x1, y1, colors: parts }; +} + +function parseRadialGradient(layer: string, width: number, height: number) { + const inside = layer.slice(layer.indexOf("(") + 1, layer.lastIndexOf(")")); + const parts = splitBackgroundLayers(inside); + const first = (parts.shift() || "").trim(); + + let cx = width / 2; + let cy = height / 2; + + if (first.startsWith("circle at")) { + const pos = first.replace("circle at", "").trim(); + const coords = pos.split(/\s+/); + + for (let i = 0; i < coords.length; i += 1) { + const coord = coords[i] as string; + if (coord.endsWith("%")) { + const val = parseFloat(coord) / 100; + if (i === 0) cx = val * width; + else if (i === 1) cy = val * height; + } else if (coord === "left") cx = 0; + else if (coord === "right") cx = width; + else if (coord === "top") cy = 0; + else if (coord === "bottom") cy = height; + else if (coord === "center") { + if (i === 0) cx = width / 2; + else if (i === 1) cy = height / 2; + } + } + } else { + parts.unshift(first); + } + + // Use farthest-corner for radius + const r = Math.max( + Math.hypot(cx, cy), + Math.hypot(width - cx, cy), + Math.hypot(cx, height - cy), + Math.hypot(width - cx, height - cy) + ); + + return { cx, cy, r, colors: parts }; +} + +export function drawCssBackground( + ctx: CanvasRenderingContext2D, + width: number, + height: number, + css: string +): void { + const layers = splitBackgroundLayers(css).filter(Boolean); + + // Draw layers from last to first (CSS background order) + for (let i = layers.length - 1; i >= 0; i -= 1) { + const layer = layers[i] as string; + + if (layer.startsWith("linear-gradient(")) { + const { x0, y0, x1, y1, colors } = parseLinearGradient( + layer, + width, + height + ); + const grad = ctx.createLinearGradient(x0, y0, x1, y1); + const colorStops = colors.map((c) => parseColorStop(c as string)); + + // Handle positions properly + for (let j = 0; j < colorStops.length; j += 1) { + const stop = colorStops[j] as { color: string; position?: number }; + const pos = stop.position ?? j / Math.max(1, colorStops.length - 1); + grad.addColorStop(Math.max(0, Math.min(1, pos)), stop.color); + } + + ctx.fillStyle = grad; + ctx.fillRect(0, 0, width, height); + } else if (layer.startsWith("radial-gradient(")) { + const { cx, cy, r, colors } = parseRadialGradient(layer, width, height); + const grad = ctx.createRadialGradient(cx, cy, 0, cx, cy, r); + const colorStops = colors.map((c) => parseColorStop(c as string)); + + // Handle positions properly + for (let j = 0; j < colorStops.length; j += 1) { + const stop = colorStops[j] as { color: string; position?: number }; + const pos = stop.position ?? j / Math.max(1, colorStops.length - 1); + grad.addColorStop(Math.max(0, Math.min(1, pos)), stop.color); + } + + ctx.fillStyle = grad; + ctx.fillRect(0, 0, width, height); + } else if ( + layer.startsWith("#") || + layer.startsWith("rgb") || + layer.startsWith("hsl") || + layer === "transparent" || + layer === "white" || + layer === "black" + ) { + if (layer !== "transparent") { + ctx.fillStyle = layer; + ctx.fillRect(0, 0, width, height); + } + } + } +} |
