feat: add stroke thickness

src/core/raster.c

@@ -4,112 +4,123 @@
 #include <stddef.h>
 
 void vektor_edgebuffer_add_edge(EdgeBuffer *buffer, Edge edge) {
-  if (buffer->count >= buffer->capacity) {
-    buffer->capacity = buffer->capacity ? buffer->capacity * 2 : 4;
-    buffer->edges = realloc(buffer->edges, sizeof(Edge) * buffer->capacity);
-  }
-  buffer->edges[buffer->count++] = edge;
+    if (buffer->count >= buffer->capacity) {
+        buffer->capacity = buffer->capacity ? buffer->capacity * 2 : 4;
+        buffer->edges = realloc(buffer->edges, sizeof(Edge) * buffer->capacity);
+    }
+    buffer->edges[buffer->count++] = edge;
 }
 
 void vektor_line_flatten(EdgeBuffer *buffer, VektorLine line) {
-  vektor_edgebuffer_add_edge(buffer, (Edge){line.p1, line.p2, 0});
+    vektor_edgebuffer_add_edge(buffer, (Edge){line.p1, line.p2, 0});
 }
 
 void vektor_polyline_flatten(EdgeBuffer *buffer, VektorPolyline *line) {
-  for (size_t i = 0; i + 1 < line->count; i++) {
-    vektor_edgebuffer_add_edge(buffer,
-                               (Edge){line->points[i], line->points[i + 1], 0});
-  }
+    for (size_t i = 0; i + 1 < line->count; i++) {
+        vektor_edgebuffer_add_edge(
+            buffer, (Edge){line->points[i], line->points[i + 1], 0});
+    }
 }
 
 void vektor_polygon_flatten(EdgeBuffer *buffer, VektorPolygon *pg) {
-  size_t n = pg->count;
-  if (n < 3)
-    return;
+    size_t n = pg->count;
+    if (n < 3)
+        return;
 
-  for (size_t i = 0; i < n; i++) {
-    V2 p1 = pg->points[i];
-    V2 p2 = pg->points[(i + 1) % n];
-    int winding = (p1.y < p2.y) ? +1 : -1;
-    vektor_edgebuffer_add_edge(buffer, (Edge){p1, p2, winding});
-  }
+    for (size_t i = 0; i < n; i++) {
+        V2 p1 = pg->points[i];
+        V2 p2 = pg->points[(i + 1) % n];
+        int winding = (p1.y < p2.y) ? +1 : -1;
+        vektor_edgebuffer_add_edge(buffer, (Edge){p1, p2, winding});
+    }
 }
 
 inline VektorFramebuffer vektor_framebuffer_new(unsigned int W,
                                                 unsigned int H) {
-  VektorFramebuffer fb = {
-      .width = W, .height = H, .pixels = calloc(W * H * 4, 1)};
-  return fb;
+    VektorFramebuffer fb = {
+        .width = W, .height = H, .pixels = calloc(W * H * 4, 1)};
+    return fb;
 }
 
 inline void vektor_framebuffer_putpixel(VektorFramebuffer *fb, int x, int y,
                                         VektorColor color) {
-  if ((unsigned)x >= fb->width || (unsigned)y >= fb->height)
-    return;
+    if ((unsigned)x >= fb->width || (unsigned)y >= fb->height)
+        return;
 
-  int i = (y * fb->width + x) * 4;
-  fb->pixels[i + 0] = color.r;
-  fb->pixels[i + 1] = color.g;
-  fb->pixels[i + 2] = color.b;
-  fb->pixels[i + 3] = color.a;
+    int i = (y * fb->width + x) * 4;
+    fb->pixels[i + 0] = color.r;
+    fb->pixels[i + 1] = color.g;
+    fb->pixels[i + 2] = color.b;
+    fb->pixels[i + 3] = color.a;
+}
+
+void draw_filled_circle(VektorFramebuffer *fb, int cx, int cy, int r,
+                        VektorColor color) {
+    for (int y = -r; y <= r; y++) {
+        int dx = (int)sqrt(r * r - y * y);
+        for (int x = -dx; x <= dx; x++) {
+            vektor_framebuffer_putpixel(fb, cx + x, cy + y, color);
+        }
+    }
 }
 
 void vektor_framebuffer_drawline(VektorFramebuffer *fb, V2 a, V2 b,
-                                 VektorColor color) {
-  int x0 = (int)a.x;
-  int y0 = (int)a.y;
-  int x1 = (int)b.x;
-  int y1 = (int)b.y;
+                                 VektorColor color, double thickness) {
+    int x0 = (int)a.x;
+    int y0 = (int)a.y;
+    int x1 = (int)b.x;
+    int y1 = (int)b.y;
 
-  int dx = abs(x1 - x0);
-  int sx = x0 < x1 ? 1 : -1;
-  int dy = -abs(y1 - y0);
-  int sy = y0 < y1 ? 1 : -1;
-  int err = dx + dy;
+    int dx = abs(x1 - x0);
+    int sx = x0 < x1 ? 1 : -1;
+    int dy = -abs(y1 - y0);
+    int sy = y0 < y1 ? 1 : -1;
+    int err = dx + dy;
 
-  for (;;) {
-    vektor_framebuffer_putpixel(fb, x0, y0, color);
-    if (x0 == x1 && y0 == y1)
-      break;
+    for (;;) {
+        draw_filled_circle(fb, x0, y0, thickness / 2, color);
+        if (x0 == x1 && y0 == y1)
+            break;
 
-    int e2 = 2 * err;
-    if (e2 >= dy) {
-      err += dy;
-      x0 += sx;
+        int e2 = 2 * err;
+        if (e2 >= dy) {
+            err += dy;
+            x0 += sx;
+        }
+        if (e2 <= dx) {
+            err += dx;
+            y0 += sy;
+        }
     }
-    if (e2 <= dx) {
-      err += dx;
-      y0 += sy;
-    }
-  }
 }
 
-void vektor_framebuffer_rasterize(VektorFramebuffer *fb, VektorPrimitiveBuffer *prims) {
-  EdgeBuffer edges = {0};
-  for (size_t i = 0; i < prims->count; i++) {
-    VektorPrimitive *p = &prims->primitives[i];
+void vektor_framebuffer_rasterize(VektorFramebuffer *fb,
+                                  VektorPrimitiveBuffer *prims) {
+    EdgeBuffer edges = {0};
+    for (size_t i = 0; i < prims->count; i++) {
+        VektorPrimitive *p = &prims->primitives[i];
 
-    switch (p->kind) {
-    case VEKTOR_LINE:
-      vektor_line_flatten(&edges, p->line);
-      break;
+        switch (p->kind) {
+        case VEKTOR_LINE:
+            vektor_line_flatten(&edges, p->line);
+            break;
 
-    case VEKTOR_POLYLINE:
-      vektor_polyline_flatten(&edges, p->polyline);
-      break;
+        case VEKTOR_POLYLINE:
+            vektor_polyline_flatten(&edges, p->polyline);
+            break;
 
-    case VEKTOR_POLYGON:
-      vektor_polygon_flatten(&edges, p->polygon);
-      break;
+        case VEKTOR_POLYGON:
+            vektor_polygon_flatten(&edges, p->polygon);
+            break;
 
-    default:
-      // TODO fill in all primitives
-      break;
+        default:
+            // TODO fill in all primitives
+            break;
+        }
     }
-  }
 
-  for (size_t i = 0; i < edges.count; i++) {
-    vektor_framebuffer_drawline(fb, edges.edges[i].p1, edges.edges[i].p2,
-                                vektor_color_solid(255, 0, 255));
-  }
+    for (size_t i = 0; i < edges.count; i++) {
+        vektor_framebuffer_drawline(fb, edges.edges[i].p1, edges.edges[i].p2,
+                                    vektor_color_solid(255, 0, 255), 4);
+    }
 }