Update VLWCompress\readme.md

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Used to transform 8bit VLW file into 4bit VLW file with no padding support.
**Advantage**: It will save at least 50% space.
**Limitation**: Fonts that height over 255 are not being generated properly.
To Compile,run the command below:
@ -13,7 +14,9 @@ To Compile,run the command below:
#### Compressed Font format
Header of vlw file is the same as uncompressed;it comprises 6 uint32_t parameters (24 bytes total):
1. The gCount (number of character glyphs)
2. A version number (0xB = 11 for uncompressed,0XC = 12 for compressed 4bit)
3. The font size (in points, not pixels)
@ -22,6 +25,7 @@ Header of vlw file is the same as uncompressed;it comprises 6 uint32_t parameter
6. Descent in pixels from baseline to bottom of "p"
Next are gCount sets of values for each glyph(8 bytes):
1. (16 bits) Glyph Unicode
2. (8 bits) Height of bitmap bounding box
3. (8 bits) Width of bitmap bounding box
@ -33,11 +37,12 @@ Header of vlw file is the same as uncompressed;it comprises 6 uint32_t parameter
Each pixel is 0.5 byte, an 4 bit Alpha value which represents the transparency from
0xF foreground colour, 0x0 background.When a line consist of odd number of pixels,the last byte
for the last pixel of the line will be filled with 0 as low 4 bits.
4 bits alpha value will be generated to 8 bits before drawing.
4 bits alpha value will be converted to 8 bits before drawing.
After the bitmaps is (Not modified):
1 byte for font name string length (excludes null)
a zero terminated character string giving the font name
1 byte for Postscript name string length
a zero/one terminated character string giving the font name
last byte is 0 for non-anti-aliased and 1 for anti-aliased (smoothed)
- 1 byte for font name string length (excludes null)
- a zero terminated character string giving the font name
- 1 byte for Postscript name string length
- a zero/one terminated character string giving the font name
- last byte is 0 for non-anti-aliased and 1 for anti-aliased (smoothed)