初始化奇妙小屏幕控制器项目

2026-09-08 22:56:52 +08:00
commit 8d368de3b5
491 changed files with 67678 additions and 0 deletions
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+const OUTPUT_PIXELS = 64;
+
+function positiveNumber(value, field) {
+  const number = Number(value);
+  if (!Number.isFinite(number) || number <= 0) {
+    throw new TypeError(field + " must be a positive number");
+  }
+  return number;
+}
+
+export function cropGeometry({
+  viewportWidth, viewportHeight, sourceWidth, sourceHeight, zoom, centerX, centerY,
+}) {
+  const viewWidth = positiveNumber(viewportWidth, "viewportWidth");
+  const viewHeight = positiveNumber(viewportHeight, "viewportHeight");
+  const imageWidth = positiveNumber(sourceWidth, "sourceWidth");
+  const imageHeight = positiveNumber(sourceHeight, "sourceHeight");
+  const scaleZoom = positiveNumber(zoom, "zoom");
+  const x = Number(centerX), y = Number(centerY);
+  if (!Number.isFinite(x) || !Number.isFinite(y)) {
+    throw new TypeError("crop center must be finite");
+  }
+  const scale = Math.min(viewWidth / imageWidth, viewHeight / imageHeight) * scaleZoom;
+  const width = imageWidth * scale;
+  const height = imageHeight * scale;
+  return {
+    width,
+    height,
+    left: viewWidth / 2 - x * width,
+    top: viewHeight / 2 - y * height,
+  };
+}
+
+export function cropCenterBounds({
+  viewportWidth, viewportHeight, sourceWidth, sourceHeight, zoom,
+}) {
+  const geometry = cropGeometry({
+    viewportWidth, viewportHeight, sourceWidth, sourceHeight, zoom,
+    centerX: 0.5, centerY: 0.5,
+  });
+  const visibleX = Math.min(Number(viewportWidth) / OUTPUT_PIXELS, geometry.width);
+  const visibleY = Math.min(Number(viewportHeight) / OUTPUT_PIXELS, geometry.height);
+  return {
+    minX: (visibleX - Number(viewportWidth) / 2) / geometry.width,
+    maxX: 1 + (Number(viewportWidth) / 2 - visibleX) / geometry.width,
+    minY: (visibleY - Number(viewportHeight) / 2) / geometry.height,
+    maxY: 1 + (Number(viewportHeight) / 2 - visibleY) / geometry.height,
+  };
+}
+
+export function clampCropCenter(value, bounds) {
+  return {
+    centerX: Math.max(bounds.minX, Math.min(bounds.maxX, Number(value.centerX))),
+    centerY: Math.max(bounds.minY, Math.min(bounds.maxY, Number(value.centerY))),
+  };
+}