System/Utilities/TrueType: Add TrueType font support via stb_truetype.h

src/truetype/truetype.c

@@ -0,0 +1,52 @@
+#define STB_TRUETYPE_IMPLEMENTATION
+#include "stb_truetype.h"
+
+unsigned char* stbtt_RenderText(stbtt_fontinfo* info, int b_w, int b_h, int l_h, char* word)
+{
+    // https://github.com/justinmeiners/stb-truetype-example
+    /* create a bitmap for the phrase */
+    unsigned char* bitmap = calloc(b_w * b_h, sizeof(unsigned char));
+
+    /* calculate font scaling */
+    float scale = stbtt_ScaleForPixelHeight(info, l_h);
+
+    int x = 0;
+
+    int ascent, descent, lineGap;
+    stbtt_GetFontVMetrics(info, &ascent, &descent, &lineGap);
+
+    ascent = roundf(ascent * scale);
+    descent = roundf(descent * scale);
+
+    int i;
+    for (i = 0; i < strlen(word); ++i) {
+        /* how wide is this character */
+        int ax;
+        int lsb;
+        stbtt_GetCodepointHMetrics(info, word[i], &ax, &lsb);
+        /* (Note that each Codepoint call has an alternative Glyph version which caches the work required to lookup the character word[i].) */
+
+        /* get bounding box for character (may be offset to account for chars that dip above or below the line) */
+        int c_x1, c_y1, c_x2, c_y2;
+        stbtt_GetCodepointBitmapBox(info, word[i], scale, scale, &c_x1, &c_y1, &c_x2, &c_y2);
+
+        /* compute y (different characters have different heights) */
+        int y = ascent + c_y1;
+
+        /* render character (stride and offset is important here) */
+        int byteOffset = x + roundf(lsb * scale) + (y * b_w);
+        stbtt_MakeCodepointBitmap(info, bitmap + byteOffset, c_x2 - c_x1, c_y2 - c_y1, b_w, scale, scale, word[i]);
+
+        /* advance x */
+        x += roundf(ax * scale);
+
+        /* add kerning */
+        int kern;
+        kern = stbtt_GetCodepointKernAdvance(info, word[i], word[i + 1]);
+        x += roundf(kern * scale);
+    }
+
+    return bitmap;
+}
+
+int main() { return 0; }