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fix(pdf): revert RGB_565 — PdfRenderer requires ARGB_8888

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PdfRenderer.Page.render() only accepts ARGB_8888 bitmaps; RGB_565 is
silently rejected (the renderer produces no output), which is why the
preview card and viewer both stopped showing anything. Go back to
ARGB_8888 and update the memory estimates in the comments. The other
perf wins from 49e913b (FilterQuality.Medium, 4096 hi-res cap, 1.5x
threshold, remembered ImageBitmap wrapper) are unaffected and stay.
This commit is contained in:
Claude
2026-04-19 17:19:36 +00:00
parent 49e913bec4
commit 496cc9876f
2 changed files with 9 additions and 11 deletions
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amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/pdf/PdfPreviewCard.kt
+2 -3
View File
@@ -256,9 +256,8 @@ private fun renderFirstPage(
renderer.openPage(0).use { page ->
val (renderW, renderH) = cappedRenderSize(page.width, page.height, targetWidthPx)
// RGB_565 halves memory vs ARGB_8888 and is visually identical for
// opaque PDF renders.
val bitmap = Bitmap.createBitmap(renderW, renderH, Bitmap.Config.RGB_565)
// PdfRenderer requires ARGB_8888; RGB_565 silently produces blank output.
val bitmap = Bitmap.createBitmap(renderW, renderH, Bitmap.Config.ARGB_8888)
bitmap.eraseColor(android.graphics.Color.WHITE)
page.render(bitmap, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY)
PdfLoadState.Ready(
amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/pdf/PdfViewerDialog.kt
+7 -8
View File
@@ -89,16 +89,16 @@ import net.engawapg.lib.zoomable.toggleScale
import net.engawapg.lib.zoomable.zoomable
// Hard ceiling on each base-rendered page bitmap, in pixels. Higher = sharper when
// the user pinch-zooms inside the dialog, but each page costs ~maxDim^2 * 2 bytes
// of RAM (RGB_565). 3072 gives ~13 MB per A4-shaped page.
// the user pinch-zooms inside the dialog, but each page costs ~maxDim^2 * 4 bytes
// of RAM (PdfRenderer requires ARGB_8888). 3072 gives ~26 MB per A4-shaped page.
private const val VIEWER_MAX_DIM_PX = 3072
// Hard ceiling for the per-page zoom-aware detail render. When the user zooms in
// past HI_RES_ZOOM_THRESHOLD we re-render the current page at
// (VIEWER_MAX_DIM_PX * scale) capped at this value. 4096 keeps the bitmap within
// common GPU texture limits (so drawing stays hardware-accelerated) and caps
// memory at ~24 MB for an A4-shaped page (RGB_565). Above 4096 most mid-range
// GPUs fall back to software rendering, which is what caused the pan/zoom jitter.
// memory at ~48 MB for an A4-shaped page. Above 4096 most mid-range GPUs fall
// back to software rendering, which is what caused the pan/zoom jitter.
private const val HI_RES_MAX_DIM_PX = 4096
private const val HI_RES_ZOOM_THRESHOLD = 1.5f
private const val HI_RES_DEBOUNCE_MS = 200L
@@ -398,10 +398,9 @@ private suspend fun renderPageCatching(
withContext(Dispatchers.IO) {
handle.renderer.openPage(pageIndex).use { page ->
val (width, height) = cappedRenderSize(page.width, page.height, maxDim)
// RGB_565 uses half the memory of ARGB_8888 and is indistinguishable
// for PDFs (opaque white background, no alpha). Halves GPU texture
// upload size and sampling cost during pan/zoom.
val bmp = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565)
// PdfRenderer requires ARGB_8888 bitmaps — RGB_565 is silently
// rejected and produces blank output.
val bmp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888)
bmp.eraseColor(android.graphics.Color.WHITE)
page.render(bmp, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY)
bmp