Import AITURK IDE 1.0.0-beta.1 from Hermes 63279301; preserve MIT license

apps/desktop/electron/preview-capture.ts

@@ -0,0 +1,131 @@
+/**
+ * Crop a preview webview via webContents.capturePage.
+ *
+ * Electron's rect argument is unreliable on guest webviews (empty NativeImage
+ * on Windows, DPI-shifted crops). Capture the visible viewport, then crop in
+ * bitmap space from CSS viewport coordinates.
+ *
+ * Missing/destroyed guests fail closed — never a blank PNG that would look
+ * like a successful shot of nothing.
+ */
+
+export interface CaptureRect {
+  height: number
+  width: number
+  x: number
+  y: number
+}
+
+export interface CaptureViewport {
+  height: number
+  width: number
+}
+
+export interface CaptureGuest {
+  capturePage: (rect?: CaptureRect) => Promise<CaptureImage>
+  isDestroyed: () => boolean
+}
+
+export interface CaptureImage {
+  crop?: (rect: CaptureRect) => CaptureImage
+  getSize?: () => CaptureViewport
+  isEmpty: () => boolean
+  toPNG: () => Buffer
+}
+
+export function normalizeCaptureRect(rect?: CaptureRect): CaptureRect | undefined {
+  if (!rect) {
+    return undefined
+  }
+
+  return {
+    height: Math.max(1, Math.ceil(rect.height)),
+    width: Math.max(1, Math.ceil(rect.width)),
+    x: Math.max(0, Math.floor(rect.x)),
+    y: Math.max(0, Math.floor(rect.y))
+  }
+}
+
+/** Map a CSS-pixel viewport rect onto a (possibly DPR-scaled) bitmap. */
+export function mapViewportRectToImage(
+  rect: CaptureRect,
+  viewport: CaptureViewport,
+  image: CaptureViewport
+): CaptureRect | null {
+  const viewW = Math.max(1, viewport.width)
+  const viewH = Math.max(1, viewport.height)
+  const scaleX = image.width / viewW
+  const scaleY = image.height / viewH
+  const left = rect.x * scaleX
+  const top = rect.y * scaleY
+  const right = (rect.x + rect.width) * scaleX
+  const bottom = (rect.y + rect.height) * scaleY
+  const x = Math.max(0, Math.floor(left))
+  const y = Math.max(0, Math.floor(top))
+  const maxX = Math.min(image.width, Math.ceil(right))
+  const maxY = Math.min(image.height, Math.ceil(bottom))
+  const width = maxX - x
+  const height = maxY - y
+
+  if (width < 1 || height < 1) {
+    return null
+  }
+
+  return { height, width, x, y }
+}
+
+function toDataUrl(image: CaptureImage): string {
+  if (!image || image.isEmpty()) {
+    throw new Error('preview capture was empty')
+  }
+
+  return `data:image/png;base64,${image.toPNG().toString('base64')}`
+}
+
+export async function capturePreviewContents(
+  guest: CaptureGuest | null | undefined,
+  rect?: CaptureRect,
+  viewport?: CaptureViewport
+): Promise<string> {
+  if (!guest || guest.isDestroyed()) {
+    throw new Error('preview guest is gone')
+  }
+
+  const image = await guest.capturePage()
+
+  if (!image || image.isEmpty()) {
+    throw new Error('preview capture was empty')
+  }
+
+  const crop = normalizeCaptureRect(rect)
+
+  if (!crop) {
+    return toDataUrl(image)
+  }
+
+  const size = image.getSize?.()
+  const view = viewport && viewport.width > 0 && viewport.height > 0 ? viewport : size
+
+  if (size && view && typeof image.crop === 'function') {
+    const mapped = mapViewportRectToImage(crop, view, size)
+
+    if (mapped) {
+      const cropped = image.crop(mapped)
+
+      if (cropped && !cropped.isEmpty()) {
+        return toDataUrl(cropped)
+      }
+    }
+
+    // Off-screen CSS rects (document Y after scroll, DPI mismatch) used to
+    // throw here and the composer kept the stale pick-time crop. The visible
+    // page is a better fallback than the wrong slice of the article.
+    return toDataUrl(image)
+  }
+
+  try {
+    return toDataUrl(await guest.capturePage(crop))
+  } catch {
+    return toDataUrl(image)
+  }
+}