cottongin/crosspoint-reader
Archived
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases 4 Wiki Activity

feat(home): Add cover image thumbnail to Continue Reading card

Browse Source 
Display book cover image as background in the Continue Reading card on
the home screen, improving visual identification of the current book.

Key changes:
- Add thumbnail generation (thumb.bmp) for EPUB and XTC/XTCH files
  - Uses same dithering/scaling algorithms as sleep screen covers
  - Target size: 240x400 (half screen) for optimal Continue Reading card fit
- Add JpegToBmpConverter::jpegFileToBmpStreamWithSize() for custom target sizes
- Add GfxRenderer::copyStoredBwBuffer() and freeStoredBwBuffer() for
  framebuffer caching to maintain fast navigation performance
- Add UTF-8 safe string truncation for Korean/CJK text in title/author display
- Draw white boxes behind title/author text for readability over cover image
- Increase HomeActivityTask stack size to 4096 for cover image rendering
- Add bounds checking in XTC thumbnail generation to prevent buffer overflow
This commit is contained in:
Eunchurn Park
2026-01-01 19:02:05 +09:00
parent 04ad4e5aa4
commit 6fbdd06101
10 changed files with 667 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
lib/JpegToBmpConverter/JpegToBmpConverter.cpp
View File

@@ -356,7 +356,7 @@ void writeBmpHeader8bit(Print& bmpOut, const int width, const int height) {
}
// Helper function: Write BMP header with 2-bit color depth
void JpegToBmpConverter::writeBmpHeader(Print& bmpOut, const int width, const int height) {
static void writeBmpHeader2bit(Print& bmpOut, const int width, const int height) {
// Calculate row padding (each row must be multiple of 4 bytes)
const int bytesPerRow = (width * 2 + 31) / 32 * 4; // 2 bits per pixel, round up
const int imageSize = bytesPerRow * height;
@@ -427,9 +427,10 @@ unsigned char JpegToBmpConverter::jpegReadCallback(unsigned char* pBuf, const un
return 0; // Success
}
// Core function: Convert JPEG file to 2-bit BMP
bool JpegToBmpConverter::jpegFileToBmpStream(FsFile& jpegFile, Print& bmpOut) {
Serial.printf("[%lu] [JPG] Converting JPEG to BMP\n", millis());
// Internal implementation with configurable target size
bool JpegToBmpConverter::jpegFileToBmpStreamInternal(FsFile& jpegFile, Print& bmpOut, int targetWidth,
int targetHeight) {
Serial.printf("[%lu] [JPG] Converting JPEG to BMP (target: %dx%d)\n", millis(), targetWidth, targetHeight);
// Setup context for picojpeg callback
JpegReadContext context = {.file = jpegFile, .bufferPos = 0, .bufferFilled = 0};
@@ -464,10 +465,10 @@ bool JpegToBmpConverter::jpegFileToBmpStream(FsFile& jpegFile, Print& bmpOut) {
uint32_t scaleY_fp = 65536;
bool needsScaling = false;
if (USE_PRESCALE && (imageInfo.m_width > TARGET_MAX_WIDTH || imageInfo.m_height > TARGET_MAX_HEIGHT)) {
if (targetWidth > 0 && targetHeight > 0 && (imageInfo.m_width > targetWidth || imageInfo.m_height > targetHeight)) {
// Calculate scale to fit within target dimensions while maintaining aspect ratio
const float scaleToFitWidth = static_cast<float>(TARGET_MAX_WIDTH) / imageInfo.m_width;
const float scaleToFitHeight = static_cast<float>(TARGET_MAX_HEIGHT) / imageInfo.m_height;
const float scaleToFitWidth = static_cast<float>(targetWidth) / imageInfo.m_width;
const float scaleToFitHeight = static_cast<float>(targetHeight) / imageInfo.m_height;
const float scale = (scaleToFitWidth < scaleToFitHeight) ? scaleToFitWidth : scaleToFitHeight;
outWidth = static_cast<int>(imageInfo.m_width * scale);
@@ -484,7 +485,7 @@ bool JpegToBmpConverter::jpegFileToBmpStream(FsFile& jpegFile, Print& bmpOut) {
needsScaling = true;
Serial.printf("[%lu] [JPG] Pre-scaling %dx%d -> %dx%d (fit to %dx%d)\n", millis(), imageInfo.m_width,
imageInfo.m_height, outWidth, outHeight, TARGET_MAX_WIDTH, TARGET_MAX_HEIGHT);
imageInfo.m_height, outWidth, outHeight, targetWidth, targetHeight);
}
// Write BMP header with output dimensions
@@ -493,7 +494,7 @@ bool JpegToBmpConverter::jpegFileToBmpStream(FsFile& jpegFile, Print& bmpOut) {
writeBmpHeader8bit(bmpOut, outWidth, outHeight);
bytesPerRow = (outWidth + 3) / 4 * 4;
} else {
writeBmpHeader(bmpOut, outWidth, outHeight);
writeBmpHeader2bit(bmpOut, outWidth, outHeight);
bytesPerRow = (outWidth * 2 + 31) / 32 * 4;
}
@@ -736,3 +737,14 @@ bool JpegToBmpConverter::jpegFileToBmpStream(FsFile& jpegFile, Print& bmpOut) {
Serial.printf("[%lu] [JPG] Successfully converted JPEG to BMP\n", millis());
return true;
}
// Core function: Convert JPEG file to 2-bit BMP (uses default target size)
bool JpegToBmpConverter::jpegFileToBmpStream(FsFile& jpegFile, Print& bmpOut) {
return jpegFileToBmpStreamInternal(jpegFile, bmpOut, TARGET_MAX_WIDTH, TARGET_MAX_HEIGHT);
}
// Convert with custom target size (for thumbnails)
bool JpegToBmpConverter::jpegFileToBmpStreamWithSize(FsFile& jpegFile, Print& bmpOut, int targetMaxWidth,
int targetMaxHeight) {
return jpegFileToBmpStreamInternal(jpegFile, bmpOut, targetMaxWidth, targetMaxHeight);
}