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40 lines
1.4 KiB
Markdown
40 lines
1.4 KiB
Markdown
Tutorial 0A - PC Screen Font
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============================
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Drawing pixmaps is fun, but definitely there's a need to display characters as well. Basicaly fonts
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are nothing more than bitmaps for each character. For this tutorial I choosed PC Screen Font format,
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the same Linux Console uses.
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Lfb.h, lfb.c
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------------
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`lfb_init()` sets up resolution, depth, and color channel order. Also queries framebuffer's address.
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`lfb_print(x,y,s)` displays a string on screen.
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Font.psf
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--------
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The font file. Use any file from /usr/share/kbd/consolefonts. Unicode table is not supported. Translating
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characters to glyph index using that table (instead of one-to-one relation) is a homework for you. This font
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is generated from the original IBM PC VGA 8x16 Font ROM, and includes 127 glyphs.
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Makefile
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--------
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I've added a new object file, generated from the psf. It's a good example of how to include and reference
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a binary file in C. I've used the following command to find out the label:
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```sh
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$ aarch64-elf-readelf -s font.o
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... output removed for clearity ...
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2: 0000000000000820 0 NOTYPE GLOBAL DEFAULT 1 _binary_font_psf_end
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3: 0000000000000000 0 NOTYPE GLOBAL DEFAULT 1 _binary_font_psf_start
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4: 0000000000000820 0 NOTYPE GLOBAL DEFAULT ABS _binary_font_psf_size
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```
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Main
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----
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Very simple. We set the resolution and display the string.
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