A fork of https://github.com/crosspoint-reader/crosspoint-reader
refactor: Deduplicated BMP header writing in Xtc (#1439)
## Summary
**What is the goal of this PR?**
Replaced manual 1-bit BMP header logic in `Xtc::generateCoverBmp()` and
`Xtc::generateThumbBmp()` with calls to the existing `createBmpHeader()`
utility. Added a `BmpRowOrder` enum and param to support the top-down
row order of XTC cover images.
---
### AI Usage
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authored by
Zach Nelson
and committed by
GitHub
5ba85290
104f391a
+21
-95
+6
-6
lib/GfxRenderer/BitmapHelpers.cpp
+6
-6
lib/GfxRenderer/BitmapHelpers.cpp
···
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return (gray >= adjustedThreshold) ? 1 : 0;
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}
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void createBmpHeader(BmpHeader* bmpHeader, int width, int height) {
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void createBmpHeader(BmpHeader* bmpHeader, int width, int height, BmpRowOrder rowOrder) {
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if (!bmpHeader) return;
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// Zero out the memory to ensure no garbage data if called on uninitialized stack memory
···
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bmpHeader->infoHeader.biSize = sizeof(bmpHeader->infoHeader);
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bmpHeader->infoHeader.biWidth = width;
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bmpHeader->infoHeader.biHeight = height;
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bmpHeader->infoHeader.biHeight = (rowOrder == BmpRowOrder::TopDown) ? -height : height;
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bmpHeader->infoHeader.biPlanes = 1;
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bmpHeader->infoHeader.biBitCount = 1;
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bmpHeader->infoHeader.biCompression = 0;
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bmpHeader->infoHeader.biSizeImage = imageSize;
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bmpHeader->infoHeader.biXPelsPerMeter = 0;
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bmpHeader->infoHeader.biYPelsPerMeter = 0;
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bmpHeader->infoHeader.biClrUsed = 0;
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bmpHeader->infoHeader.biClrImportant = 0;
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bmpHeader->infoHeader.biXPelsPerMeter = 2835; // 72 DPI
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bmpHeader->infoHeader.biYPelsPerMeter = 2835; // 72 DPI
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bmpHeader->infoHeader.biClrUsed = 2;
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bmpHeader->infoHeader.biClrImportant = 2;
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// Color 0 (black)
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bmpHeader->colors[0].rgbBlue = 0;
+3
-1
lib/GfxRenderer/BitmapHelpers.h
+3
-1
lib/GfxRenderer/BitmapHelpers.h
···
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uint8_t quantize1bit(int gray, int x, int y);
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int adjustPixel(int gray);
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enum class BmpRowOrder { BottomUp, TopDown };
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// Populates a 1-bit BMP header in the provided memory.
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void createBmpHeader(BmpHeader* bmpHeader, int width, int height);
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void createBmpHeader(BmpHeader* bmpHeader, int width, int height, BmpRowOrder rowOrder);
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// 1-bit Atkinson dithering - better quality than noise dithering for thumbnails
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// Error distribution pattern (same as 2-bit but quantizes to 2 levels):
+11
-87
lib/Xtc/Xtc.cpp
+11
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lib/Xtc/Xtc.cpp
···
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#include "Xtc.h"
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#include <Bitmap.h>
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#include <HalStorage.h>
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#include <Logging.h>
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···
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return false;
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}
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// Write BMP header
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// BMP file header (14 bytes)
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const uint32_t rowSize = ((pageInfo.width + 31) / 32) * 4; // Row size aligned to 4 bytes
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const uint32_t imageSize = rowSize * pageInfo.height;
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const uint32_t fileSize = 14 + 40 + 8 + imageSize; // Header + DIB + palette + data
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// File header
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coverBmp.write('B');
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coverBmp.write('M');
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coverBmp.write(reinterpret_cast<const uint8_t*>(&fileSize), 4);
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uint32_t reserved = 0;
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coverBmp.write(reinterpret_cast<const uint8_t*>(&reserved), 4);
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uint32_t dataOffset = 14 + 40 + 8; // 1-bit palette has 2 colors (8 bytes)
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coverBmp.write(reinterpret_cast<const uint8_t*>(&dataOffset), 4);
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// DIB header (BITMAPINFOHEADER - 40 bytes)
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uint32_t dibHeaderSize = 40;
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coverBmp.write(reinterpret_cast<const uint8_t*>(&dibHeaderSize), 4);
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int32_t width = pageInfo.width;
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coverBmp.write(reinterpret_cast<const uint8_t*>(&width), 4);
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int32_t height = -static_cast<int32_t>(pageInfo.height); // Negative for top-down
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coverBmp.write(reinterpret_cast<const uint8_t*>(&height), 4);
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uint16_t planes = 1;
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coverBmp.write(reinterpret_cast<const uint8_t*>(&planes), 2);
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uint16_t bitsPerPixel = 1; // 1-bit monochrome
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coverBmp.write(reinterpret_cast<const uint8_t*>(&bitsPerPixel), 2);
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uint32_t compression = 0; // BI_RGB (no compression)
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coverBmp.write(reinterpret_cast<const uint8_t*>(&compression), 4);
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coverBmp.write(reinterpret_cast<const uint8_t*>(&imageSize), 4);
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int32_t ppmX = 2835; // 72 DPI
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coverBmp.write(reinterpret_cast<const uint8_t*>(&ppmX), 4);
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int32_t ppmY = 2835;
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coverBmp.write(reinterpret_cast<const uint8_t*>(&ppmY), 4);
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uint32_t colorsUsed = 2;
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coverBmp.write(reinterpret_cast<const uint8_t*>(&colorsUsed), 4);
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uint32_t colorsImportant = 2;
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coverBmp.write(reinterpret_cast<const uint8_t*>(&colorsImportant), 4);
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// Write 1-bit BMP header (top-down row order)
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BmpHeader bmpHeader;
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createBmpHeader(&bmpHeader, pageInfo.width, pageInfo.height, BmpRowOrder::TopDown);
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coverBmp.write(reinterpret_cast<const uint8_t*>(&bmpHeader), sizeof(bmpHeader));
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// Color palette (2 colors for 1-bit)
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// XTC 1-bit polarity: 0 = black, 1 = white (standard BMP palette order)
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// Color 0: Black (text/foreground in XTC)
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uint8_t black[4] = {0x00, 0x00, 0x00, 0x00};
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coverBmp.write(black, 4);
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// Color 1: White (background in XTC)
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uint8_t white[4] = {0xFF, 0xFF, 0xFF, 0x00};
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coverBmp.write(white, 4);
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const uint32_t rowSize = ((pageInfo.width + 31) / 32) * 4;
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// Write bitmap data
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// BMP requires 4-byte row alignment
···
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return false;
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}
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// Write 1-bit BMP header for fast home screen rendering
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const uint32_t rowSize = (thumbWidth + 31) / 32 * 4; // 1 bit per pixel, aligned to 4 bytes
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const uint32_t imageSize = rowSize * thumbHeight;
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const uint32_t fileSize = 14 + 40 + 8 + imageSize; // 8 bytes for 2-color palette
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// File header
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thumbBmp.write('B');
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thumbBmp.write('M');
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&fileSize), 4);
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uint32_t reserved = 0;
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&reserved), 4);
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uint32_t dataOffset = 14 + 40 + 8; // 1-bit palette has 2 colors (8 bytes)
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&dataOffset), 4);
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// Write 1-bit BMP header (top-down row order)
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BmpHeader bmpHeader;
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createBmpHeader(&bmpHeader, thumbWidth, thumbHeight, BmpRowOrder::TopDown);
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&bmpHeader), sizeof(bmpHeader));
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// DIB header
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uint32_t dibHeaderSize = 40;
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&dibHeaderSize), 4);
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int32_t widthVal = thumbWidth;
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&widthVal), 4);
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int32_t heightVal = -static_cast<int32_t>(thumbHeight); // Negative for top-down
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&heightVal), 4);
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uint16_t planes = 1;
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&planes), 2);
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uint16_t bitsPerPixel = 1; // 1-bit for black and white
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&bitsPerPixel), 2);
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uint32_t compression = 0;
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&compression), 4);
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&imageSize), 4);
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int32_t ppmX = 2835;
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&ppmX), 4);
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int32_t ppmY = 2835;
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&ppmY), 4);
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uint32_t colorsUsed = 2;
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&colorsUsed), 4);
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uint32_t colorsImportant = 2;
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thumbBmp.write(reinterpret_cast<const uint8_t*>(&colorsImportant), 4);
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// Color palette (2 colors for 1-bit: black and white)
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uint8_t palette[8] = {
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0x00, 0x00, 0x00, 0x00, // Color 0: Black
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0xFF, 0xFF, 0xFF, 0x00 // Color 1: White
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};
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thumbBmp.write(palette, 8);
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const uint32_t rowSize = (thumbWidth + 31) / 32 * 4;
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// Allocate row buffer for 1-bit output
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uint8_t* rowBuffer = static_cast<uint8_t*>(malloc(rowSize));
+1
-1
src/util/ScreenshotUtil.cpp
+1
-1
src/util/ScreenshotUtil.cpp