.ttf fonts (beta)

src/kernel/font_manager.c

@@ -0,0 +1,159 @@
+#define STB_TRUETYPE_IMPLEMENTATION
+#include "memory_manager.h"
+#include "font_manager.h"
+#include "stb_truetype.h"
+#include "fat32.h"
+#include <stddef.h>
+
+// Simple math implementations for stb_truetype
+float ksqrtf(float x) {
+    float res;
+    asm volatile("sqrtss %1, %0" : "=x"(res) : "x"(x));
+    return res;
+}
+
+float kfabsf(float x) {
+    return (x < 0) ? -x : x;
+}
+
+float kpowf(float b, float e) {
+    // Very simplified pow for stb_truetype's needs
+    if (e == 0) return 1.0f;
+    if (e == 1) return b;
+    if (e == 0.5f) return ksqrtf(b);
+    
+    // Fallback/log-based would be complex, let's see if this suffices
+    float res = 1.0f;
+    for (int i = 0; i < (int)e; i++) res *= b;
+    return res;
+}
+
+float kfmodf(float x, float y) {
+    return x - (int)(x / y) * y;
+}
+
+float kcosf(float x) {
+    // Taylor series for cos(x) around 0
+    float x2 = x * x;
+    return 1.0f - (x2 / 2.0f) + (x2 * x2 / 24.0f) - (x2 * x2 * x2 / 720.0f);
+}
+
+float kacosf(float x) {
+    // Very rough approximation for acos(x)
+    if (x >= 1.0f) return 0;
+    if (x <= -1.0f) return 3.14159f;
+    return 1.57079f - x - (x*x*x)/6.0f;
+}
+
+extern void serial_write(const char *s);
+extern uint32_t graphics_get_pixel(int x, int y);
+
+static inline uint32_t alpha_blend(uint32_t bg, uint32_t fg, uint8_t alpha) {
+    if (alpha == 0) return bg;
+    if (alpha == 255) return fg;
+    
+    uint32_t rb = (((fg & 0xFF00FF) * alpha) + ((bg & 0xFF00FF) * (255 - alpha))) >> 8;
+    uint32_t g = (((fg & 0x00FF00) * alpha) + ((bg & 0x00FF00) * (255 - alpha))) >> 8;
+    return (rb & 0xFF00FF) | (g & 0x00FF00);
+}
+
+static ttf_font_t *default_font = NULL;
+
+bool font_manager_init(void) {
+    // We'll load a default font later if available
+    return true;
+}
+
+ttf_font_t* font_manager_load(const char *path, float size) {
+    FAT32_FileHandle *fh = fat32_open(path, "r");
+    if (!fh || !fh->valid) {
+        serial_write("[FONT] Failed to open font file: ");
+        serial_write(path);
+        serial_write("\n");
+        return NULL;
+    }
+
+    uint32_t fsize = fh->size;
+    unsigned char *buffer = kmalloc(fsize);
+    if (!buffer) {
+        fat32_close(fh);
+        return NULL;
+    }
+
+    int read = fat32_read(fh, buffer, fsize);
+    fat32_close(fh);
+
+    ttf_font_t *font = kmalloc(sizeof(ttf_font_t));
+    if (!font) {
+        kfree(buffer);
+        return NULL;
+    }
+
+    stbtt_fontinfo *info = kmalloc(sizeof(stbtt_fontinfo));
+    if (!info) {
+        kfree(buffer);
+        kfree(font);
+        return NULL;
+    }
+
+    if (!stbtt_InitFont(info, buffer, 0)) {
+        serial_write("[FONT] Failed to init font: ");
+        serial_write(path);
+        serial_write("\n");
+        kfree(info);
+        kfree(buffer);
+        kfree(font);
+        return NULL;
+    }
+
+    font->data = buffer;
+    font->size = fsize;
+    font->info = info;
+    font->scale = stbtt_ScaleForPixelHeight(info, size);
+    
+    stbtt_GetFontVMetrics(info, &font->ascent, &font->descent, &font->line_gap);
+
+    if (!default_font) default_font = font;
+
+    return font;
+}
+
+void font_manager_render_char(ttf_font_t *font, int x, int y, char c, uint32_t color, void (*put_pixel_fn)(int, int, uint32_t)) {
+    if (!font) font = default_font;
+    if (!font) return;
+
+    stbtt_fontinfo *info = (stbtt_fontinfo *)font->info;
+    int w, h, xoff, yoff;
+    unsigned char *bitmap = stbtt_GetCodepointBitmap(info, 0, font->scale, c, &w, &h, &xoff, &yoff);
+
+    if (bitmap) {
+        for (int row = 0; row < h; row++) {
+            for (int col = 0; col < w; col++) {
+                unsigned char alpha = bitmap[row * w + col];
+                if (alpha > 0) {
+                    int px = x + col + xoff;
+                    int py = y + row + yoff;
+                    uint32_t bg = graphics_get_pixel(px, py);
+                    put_pixel_fn(px, py, alpha_blend(bg, color, alpha));
+                }
+            }
+        }
+        stbtt_FreeBitmap(bitmap, NULL);
+    }
+}
+
+int font_manager_get_string_width(ttf_font_t *font, const char *s) {
+    if (!font) font = default_font;
+    if (!font || !s) return 0;
+
+    stbtt_fontinfo *info = (stbtt_fontinfo *)font->info;
+    int width = 0;
+    while (*s) {
+        int advance, lsb;
+        stbtt_GetCodepointHMetrics(info, *s, &advance, &lsb);
+        // Round per-character to match draw_string's accumulation
+        width += (int)(advance * font->scale + 0.5f);
+        s++;
+    }
+    return width;
+}