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refactor: Deduplicated BMP header writing in Xtc (#1439) by znelson

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This commit is contained in:
jpirnay
2026-04-10 11:29:57 +02:00
parent c42452df8e
commit c97f16b576
4 changed files with 22 additions and 96 deletions
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lib/Xtc/Xtc.cpp
+12 -88
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@@ -7,6 +7,7 @@
#include "Xtc.h"
#include <Bitmap.h>
#include <HalStorage.h>
#include <Logging.h>
@@ -175,52 +176,12 @@ bool Xtc::generateCoverBmp() const {
return false;
}
// Write BMP header
// BMP file header (14 bytes)
const uint32_t rowSize = ((pageInfo.width + 31) / 32) * 4; // Row size aligned to 4 bytes
const uint32_t imageSize = rowSize * pageInfo.height;
const uint32_t fileSize = 14 + 40 + 8 + imageSize; // Header + DIB + palette + data
// Write 1-bit BMP header (top-down row order)
BmpHeader bmpHeader;
createBmpHeader(&bmpHeader, pageInfo.width, pageInfo.height, BmpRowOrder::TopDown);
coverBmp.write(reinterpret_cast<const uint8_t*>(&bmpHeader), sizeof(bmpHeader));
// File header
coverBmp.write('B');
coverBmp.write('M');
coverBmp.write(reinterpret_cast<const uint8_t*>(&fileSize), 4);
uint32_t reserved = 0;
coverBmp.write(reinterpret_cast<const uint8_t*>(&reserved), 4);
uint32_t dataOffset = 14 + 40 + 8; // 1-bit palette has 2 colors (8 bytes)
coverBmp.write(reinterpret_cast<const uint8_t*>(&dataOffset), 4);
// DIB header (BITMAPINFOHEADER - 40 bytes)
uint32_t dibHeaderSize = 40;
coverBmp.write(reinterpret_cast<const uint8_t*>(&dibHeaderSize), 4);
int32_t width = pageInfo.width;
coverBmp.write(reinterpret_cast<const uint8_t*>(&width), 4);
int32_t height = -static_cast<int32_t>(pageInfo.height); // Negative for top-down
coverBmp.write(reinterpret_cast<const uint8_t*>(&height), 4);
uint16_t planes = 1;
coverBmp.write(reinterpret_cast<const uint8_t*>(&planes), 2);
uint16_t bitsPerPixel = 1; // 1-bit monochrome
coverBmp.write(reinterpret_cast<const uint8_t*>(&bitsPerPixel), 2);
uint32_t compression = 0; // BI_RGB (no compression)
coverBmp.write(reinterpret_cast<const uint8_t*>(&compression), 4);
coverBmp.write(reinterpret_cast<const uint8_t*>(&imageSize), 4);
int32_t ppmX = 2835; // 72 DPI
coverBmp.write(reinterpret_cast<const uint8_t*>(&ppmX), 4);
int32_t ppmY = 2835;
coverBmp.write(reinterpret_cast<const uint8_t*>(&ppmY), 4);
uint32_t colorsUsed = 2;
coverBmp.write(reinterpret_cast<const uint8_t*>(&colorsUsed), 4);
uint32_t colorsImportant = 2;
coverBmp.write(reinterpret_cast<const uint8_t*>(&colorsImportant), 4);
// Color palette (2 colors for 1-bit)
// XTC 1-bit polarity: 0 = black, 1 = white (standard BMP palette order)
// Color 0: Black (text/foreground in XTC)
uint8_t black[4] = {0x00, 0x00, 0x00, 0x00};
coverBmp.write(black, 4);
// Color 1: White (background in XTC)
uint8_t white[4] = {0xFF, 0xFF, 0xFF, 0x00};
coverBmp.write(white, 4);
const uint32_t rowSize = ((pageInfo.width + 31) / 32) * 4;
// Write bitmap data
// BMP requires 4-byte row alignment
@@ -403,49 +364,12 @@ bool Xtc::generateThumbBmp(int height) const {
return false;
}
// Write 1-bit BMP header for fast home screen rendering
const uint32_t rowSize = (thumbWidth + 31) / 32 * 4; // 1 bit per pixel, aligned to 4 bytes
const uint32_t imageSize = rowSize * thumbHeight;
const uint32_t fileSize = 14 + 40 + 8 + imageSize; // 8 bytes for 2-color palette
// Write 1-bit BMP header (top-down row order)
BmpHeader bmpHeader;
createBmpHeader(&bmpHeader, thumbWidth, thumbHeight, BmpRowOrder::TopDown);
thumbBmp.write(reinterpret_cast<const uint8_t*>(&bmpHeader), sizeof(bmpHeader));
// File header
thumbBmp.write('B');
thumbBmp.write('M');
thumbBmp.write(reinterpret_cast<const uint8_t*>(&fileSize), 4);
uint32_t reserved = 0;
thumbBmp.write(reinterpret_cast<const uint8_t*>(&reserved), 4);
uint32_t dataOffset = 14 + 40 + 8; // 1-bit palette has 2 colors (8 bytes)
thumbBmp.write(reinterpret_cast<const uint8_t*>(&dataOffset), 4);
// DIB header
uint32_t dibHeaderSize = 40;
thumbBmp.write(reinterpret_cast<const uint8_t*>(&dibHeaderSize), 4);
int32_t widthVal = thumbWidth;
thumbBmp.write(reinterpret_cast<const uint8_t*>(&widthVal), 4);
int32_t heightVal = -static_cast<int32_t>(thumbHeight); // Negative for top-down
thumbBmp.write(reinterpret_cast<const uint8_t*>(&heightVal), 4);
uint16_t planes = 1;
thumbBmp.write(reinterpret_cast<const uint8_t*>(&planes), 2);
uint16_t bitsPerPixel = 1; // 1-bit for black and white
thumbBmp.write(reinterpret_cast<const uint8_t*>(&bitsPerPixel), 2);
uint32_t compression = 0;
thumbBmp.write(reinterpret_cast<const uint8_t*>(&compression), 4);
thumbBmp.write(reinterpret_cast<const uint8_t*>(&imageSize), 4);
int32_t ppmX = 2835;
thumbBmp.write(reinterpret_cast<const uint8_t*>(&ppmX), 4);
int32_t ppmY = 2835;
thumbBmp.write(reinterpret_cast<const uint8_t*>(&ppmY), 4);
uint32_t colorsUsed = 2;
thumbBmp.write(reinterpret_cast<const uint8_t*>(&colorsUsed), 4);
uint32_t colorsImportant = 2;
thumbBmp.write(reinterpret_cast<const uint8_t*>(&colorsImportant), 4);
// Color palette (2 colors for 1-bit: black and white)
uint8_t palette[8] = {
0x00, 0x00, 0x00, 0x00, // Color 0: Black
0xFF, 0xFF, 0xFF, 0x00 // Color 1: White
};
thumbBmp.write(palette, 8);
const uint32_t rowSize = (thumbWidth + 31) / 32 * 4;
// Allocate row buffer for 1-bit output
uint8_t* rowBuffer = static_cast<uint8_t*>(malloc(rowSize));
@@ -628,4 +552,4 @@ void Xtc::prefetchPages(uint32_t pageIndex) const {
return;
}
parser->prefetchWindow(pageIndex);
}
}