f42fab1c669cb24b561d0a3fbdae7db3e14ce8bd
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Commits
| Author | SHA1 | Message | Date | |
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 martin brook
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b898d53f7b |
chore: drop JPEGDEC patch in favour of upstream fix (#1465)
## Summary The progressive JPEG fixes (AC table skip, MCU_SKIP guard) from PR #1136 have been fixed upstream in bitbank2/JPEGDEC@8628297. Pin to that commit and remove the pre-build patch script. ## Additional Context Tested on Strange Pictures epub --- ### AI Usage While CrossPoint doesn't have restrictions on AI tools in contributing, please be transparent about their usage as it helps set the right context for reviewers. Did you use AI tools to help write this code? _**< PARTIALLY >**_ |
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martin brook
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1df543d48d |
perf: Eliminate per-pixel overheads in image rendering (#1293)
## Summary Replace per-pixel getRenderMode() + rotateCoordinates() + bounds checks with a DirectPixelWriter struct that pre-computes orientation and render mode state once per row. Use bitwise ops instead of division/modulo for cache pixel packing. Skip PNG cache allocation when buffer exceeds 48KB (framebuffer size) since PNG decode is fast enough that caching provides minimal benefit, and the large buffer competes with the 44KB PNG decoder for heap. ## Additional Context Measured improvements on ESP32-C3 @ 160MHz: - JPEG decode: 5-7% faster (1:1 scale) - PNG decode: 15-20% faster (1:1 scale) - Cache renders: 3-6% faster across both formats - Eliminates "Failed to allocate cache buffer" errors for large PNGs --- ### AI Usage While CrossPoint doesn't have restrictions on AI tools in contributing, please be transparent about their usage as it helps set the right context for reviewers. Did you use AI tools to help write this code? _**< PARTIALLY >**_ |
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martin brookandDave Allie
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2b25f4d168 |
feat: replace picojpeg with JPEGDEC for JPEG image decoding (#1136)
## Summary Replaces the picojpeg library with bitbank2/JPEGDEC for JPEG decoding in the EPUB image pipeline. JPEGDEC provides built-in coarse scaling (1/2, 1/4, 1/8), 8-bit grayscale output, and streaming block-based decoding via callbacks. Includes a pre-build patch script for two JPEGDEC changes affecting progressive JPEG support and EIGHT_BIT_GRAYSCALE mode. Closes #912 ## Additional Context # Example progressive jpeg <img src="https://github.com/user-attachments/assets/e63bb4f8-f862-4aa0-a01f-d1ef43a4b27a" width="400" height="800" /> Good performance increase from JPEGDEC over picojpeg cc @bitbank2 thanks ## Baseline JPEG Decode Performance: picojpeg vs JPEGDEC (float in callback) vs JPEGDEC (fixed-point in callback) Tested with `test_jpeg_images.epub` on device (ESP32-C3), first decode (no cache). | Image | Source | Output | picojpeg | JPEGDEC float | JPEGDEC fixed-point | vs picojpeg | vs float | |-------|--------|--------|----------|---------------|---------------------|-------------|----------| | jpeg_format.jpg | 350x250 | 350x250 | 313 ms | 256 ms | **104 ms** | **3.0x** | **2.5x** | | grayscale_test.jpg | 400x600 | 400x600 | 768 ms | 661 ms | **246 ms** | **3.1x** | **2.7x** | | gradient_test.jpg | 400x500 | 400x500 | 707 ms | 597 ms | **247 ms** | **2.9x** | **2.4x** | | centering_test.jpg | 350x400 | 350x400 | 502 ms | 412 ms | **169 ms** | **3.0x** | **2.4x** | | scaling_test.jpg | 1200x1500 | 464x580 | 5487 ms | 1114 ms | **668 ms** | **8.2x** | **1.7x** | | wide_scaling_test.jpg | 1807x736 | 464x188 | 4237 ms | 642 ms | **497 ms** | **8.5x** | **1.3x** | | cache_test_1.jpg | 400x300 | 400x300 | 422 ms | 348 ms | **141 ms** | **3.0x** | **2.5x** | | cache_test_2.jpg | 400x300 | 400x300 | 424 ms | 349 ms | **142 ms** | **3.0x** | **2.5x** | ### Summary - **1:1 scale (fixed-point vs float)**: ~2.5x faster — eliminating software float on the FPU-less ESP32-C3 is the dominant win - **1:1 scale (fixed-point vs picojpeg)**: ~3.0x faster overall - **Downscaled images (vs picojpeg)**: 8-9x faster — JPEGDEC's coarse scaling + fixed-point draw callback - **Downscaled images (fixed-point vs float)**: 1.3-1.7x — less dramatic since JPEG library decode dominates over the draw callback for fewer output pixels - The fixed-point optimization alone (vs float JPEGDEC) saved **~60% of render time** on 1:1 images, confirming that software float emulation was the primary bottleneck in the draw callback - See thread for discussions on quality of progressive images, https://github.com/crosspoint-reader/crosspoint-reader/pull/1136#issuecomment-3952952315 - and the conclusion https://github.com/crosspoint-reader/crosspoint-reader/pull/1136#issuecomment-3959379386 - Proposal to improve quality added at https://github.com/crosspoint-reader/crosspoint-reader/discussions/1179 --- ### AI Usage While CrossPoint doesn't have restrictions on AI tools in contributing, please be transparent about their usage as it helps set the right context for reviewers. Did you use AI tools to help write this code? _**< PARTIALLY >**_ --------- Co-authored-by: Dave Allie <dave@daveallie.com> |
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martin brook
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f8a9f1f07a |
fix: image centering bleed (#1096)
## Summary * Fixes #1026 * Added a reproducer chapter to the epub generator for this case * The fix is in endElement — when leaving a block/header element that had an empty text block, reset the alignment to the user's default so it doesn't bleed into the next sibling. This preserves accumulated margins from parent elements while preventing stale alignment from carrying across. ## Additional Context ### Before fix    ### After fix   --- ### AI Usage While CrossPoint doesn't have restrictions on AI tools in contributing, please be transparent about their usage as it helps set the right context for reviewers. Did you use AI tools to help write this code? _**< PARTIALLY **_ |
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martin brook
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2cc497cdca |
fix: use double FAST_REFRESH to prevent washout on large grey images (#957)
## Summary Fixes https://github.com/crosspoint-reader/crosspoint-reader/issues/1011 Use double FAST_REFRESH for image pages to prevent grayscale washout, HALF_REFRESH sets e-ink particles too firmly for the grayscale LUT to adjust, causing washed-out images (especially large, light-gray ones). Replace HALF_REFRESH with @pablohc's double FAST_REFRESH technique: blank only the image bounding box area, then re-render with images. This clears ghosting while keeping particles loosely set for grayscale. ## Additional Context --- ### AI Usage While CrossPoint doesn't have restrictions on AI tools in contributing, please be transparent about their usage as it helps set the right context for reviewers. Did you use AI tools to help write this code? _**< PARTIALLY >**_ |
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martin brook
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2a38bfd8af |
fix: use double FAST_REFRESH to prevent washout on large grey images (#957)
## Summary Fixes https://github.com/crosspoint-reader/crosspoint-reader/issues/1011 Use double FAST_REFRESH for image pages to prevent grayscale washout, HALF_REFRESH sets e-ink particles too firmly for the grayscale LUT to adjust, causing washed-out images (especially large, light-gray ones). Replace HALF_REFRESH with @pablohc's double FAST_REFRESH technique: blank only the image bounding box area, then re-render with images. This clears ghosting while keeping particles loosely set for grayscale. ## Additional Context --- ### AI Usage While CrossPoint doesn't have restrictions on AI tools in contributing, please be transparent about their usage as it helps set the right context for reviewers. Did you use AI tools to help write this code? _**< PARTIALLY >**_ |
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6c3a615fac |
feat: add png jpeg support (#556)
## Summary
- Add embedded image support to EPUB rendering with JPEG and PNG
decoders
- Implement pixel caching system to cache decoded/dithered images to SD
card for faster re-rendering
- Add 4-level grayscale support for display
## Changes
### New Image Rendering System
- Add `ImageBlock` class to represent an image with its cached path and
display dimensions
- Add `PageImage` class as a new `PageElement` type for images on pages
- Add `ImageToFramebufferDecoder` interface for format-specific image
decoders
- Add `JpegToFramebufferConverter` - JPEG decoder with Bayer dithering
and scaling
- Add `PngToFramebufferConverter` - PNG decoder with Bayer dithering and
scaling
- Add `ImageDecoderFactory` to select appropriate decoder based on file
extension
- Add `getRenderMode()` to GfxRenderer for grayscale render mode queries
### Dithering and Grayscale
- Implement 4x4 Bayer ordered dithering for 4-level grayscale output
- Stateless algorithm works correctly with MCU block decoding
- Handles scaling without artifacts
- Add grayscale render mode support (BW, GRAYSCALE_LSB, GRAYSCALE_MSB)
- Image decoders and cache renderer respect current render mode
- Enables proper 4-level e-ink grayscale when anti-aliasing is enabled
### Pixel Caching
- Cache decoded/dithered images to `.pxc` files on SD card
- Cache format: 2-bit packed pixels (4 pixels per byte) with
width/height header
- On subsequent renders, load directly from cache instead of re-decoding
- Cache renderer supports grayscale render modes for multi-pass
rendering
- Significantly improves page navigation speed for image-heavy EPUBs
### HTML Parser Integration
- Update `ChapterHtmlSlimParser` to process `<img>` tags and extract
images from EPUB
- Resolve relative image paths within EPUB ZIP structure
- Extract images to cache directory before decoding
- Create `PageImage` elements with proper scaling to fit viewport
- Fall back to alt text display if image processing fails
### Build Configuration
- Add `PNG_MAX_BUFFERED_PIXELS=6402` to support up to 800px wide images
### Test Script
- Generate test EPUBs with annotated JPEG and PNG images
- Test cases cover: grayscale (4 levels), centering, scaling, cache
performance
## Test plan
- [x] Open EPUB with JPEG images - verify images display with proper
grayscale
- [x] Open EPUB with PNG images - verify images display correctly and no
crash
- [x] Navigate away from image page and back - verify faster load from
cache
- [x] Verify grayscale tones render correctly (not just black/white
dithering)
- [x] Verify large images are scaled down to fit screen
- [x] Verify images are centered horizontally
- [x] Verify page serialization/deserialization works with images
- [x] Verify images rendered in landscape mode
## Test Results
[png](https://photos.app.goo.gl/5zFUb8xA8db3dPd19)
[jpeg](https://photos.app.goo.gl/SwtwaL2DSQwKybhw7)
---
### AI Usage
Did you use AI tools to help write this code? _**< YES >**_
---------
Co-authored-by: Matthías Páll Gissurarson <mpg@mpg.is>
Co-authored-by: Dave Allie <dave@daveallie.com>
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