More work on default font rendering.

1 files changed, 90 insertions, 0 deletions

diff --git a/tools/make-font.janet b/tools/make-font.janet
new file mode 100644
index 0000000..2938632
--- /dev/null
+++ b/tools/make-font.janet
@@ -0,0 +1,90 @@
+(use spork/cjanet)
+
+(begin-jit
+  :module-name "make-font"
+  :cflags @["-Ideps/stb" "-Ideps"])
+
+(include <janet.h>)
+(include <string.h>)
+(include <math.h>)
+(include <assert.h>)
+
+(@ define STB_IMAGE_WRITE_IMPLEMENTATION)
+(@ define STB_TRUETYPE_IMPLEMENTATION)
+(@ define STBIW_WINDOWS_UTF8)
+
+(include "stb_truetype.h")
+(include "stb_image_write.h")
+
+(cfunction load-font
+  "Load a font from disk and create compressed font"
+  [path:cstring gw:int gh:int] -> int
+
+  (def fnt:stbtt-fontinfo)
+  (def font-buffer (malloc (<< 1 23)))
+  (def f (fopen path "rb"))
+  (assert (fread font-buffer 1 (<< 1 23) f))
+  (fclose f)
+
+  # Raster pixel data from stb truetype
+  (def (img-data (* char)) (malloc (* gw gh 256)))
+  (memset img-data 0 (* gw gh 256))
+
+  # Extract CP 437 fonts into a bitmap
+  (if (not (stbtt-InitFont ;fnt font-buffer 0)) (janet-panic "bad font"))
+  (def scale:float (stbtt-ScaleForPixelHeight ;fnt gh))
+  (printf "scale: %f\n" scale)
+
+  # Iterate glyphs
+  (for [(var glyph:int 1) (<= glyph 0x100) (++ glyph)]
+    #(def glyph:int (stbtt-FindGlyphIndex ;fnt codepoint))
+    #(if (= 0 glyph) (continue))
+    (var lsb:int 0)
+    (var advance:int 0)
+    (var ascent:int 0)
+    (var descent 0)
+    (var x0:int 0)
+    (var y0:int 0)
+    (var x1:int 0)
+    (var y1:int 0)
+    (stbtt-GetGlyphHMetrics ;fnt glyph ;advance ;lsb)
+    (stbtt-GetGlyphBitmapBox ;fnt glyph scale scale ;x0 ;y0 ;x1 ;y1)
+    (printf "glyph %d (x0, y0, x1, y1, advance, lsb) = (%d, %d, %d, %d, %d, %d)\n" glyph x0 y0 x1 y1 advance lsb)
+    (def pw:int (* 16 gw))
+    #(def x:int (* gw (% codepoint 16)))
+    #(def y:int (* gh (/ codepoint 16)))
+    (def x:int (+ x0 (* gw (% (- glyph 1) 16))))
+    (def y:int (+ y0 -1 gh (* gh (/ (- glyph 1) 16))))
+    (stbtt-MakeGlyphBitmap ;fnt (+ img-data x (* pw y)) gw gh pw scale scale glyph))
+  (free font-buffer)
+
+  # Write image for debugging
+  (stbi-write-png "deps/cp437_font.png" (* 16 gw) (* 16 gh) 1 img-data (* 16 gw))
+
+  # Now extract pixels into 1 bit per pixel buffer.
+  # Print the buffer as a C array
+  (def fp (fopen "deps/cp437_font.h" "wb"))
+  (fprintf fp "unsigned char cp437_font_data[] = {\n")
+  (for [(var y:int 0) (< y (* 16 gh)) (set y (+ y gh))]
+    (for [(var x:int 0) (< x (* 16 gw)) (set x (+ x gw))]
+      (fprintf fp "\n")
+      # iterate over 8x8 chunks so each glyph is 64 bits contiguous in memory
+      (for [(var yy:int y) (< yy (+ y gh)) (++ yy)]
+        (var next-byte:int 0)
+        (for [(var xx:int x) (< xx (+ x gw)) (++ xx)]
+          (if (aref img-data (+ xx (* 16 gw yy)))
+            (set next-byte (+ 1 (<< next-byte 1)))
+            (set next-byte (<< next-byte 1))))
+        (fprintf fp "0x%.2X, " next-byte))))
+  (fprintf fp "\n\n};\n")
+  (fclose fp)
+
+  (printf "Made font %s\n" path)
+
+  (return 0))
+
+(end-jit)
+
+### Save the font to a file so we can look at it
+(load-font "deps/fonts/Px437_DG_One.ttf" 8 8)
+#(load-font "deps/fonts/Px437_Nix8810_M16.ttf" 8 16)