libgfx: draw: Add gfx_copy_region()

This commit introduces a new gfx_copy_region() function that
allows a rectangular region of the screen to be defined and its
contents copied to a different part of the screen.

Signed-off-by: Ian Moffett <ian@osmora.org>

2 files changed, 56 insertions, 0 deletions

diff --git a/lib/libgfx/include/libgfx/draw.h b/lib/libgfx/include/libgfx/draw.h
index 96fe35a..8efd986 100644
--- a/lib/libgfx/include/libgfx/draw.h
+++ b/lib/libgfx/include/libgfx/draw.h
@@ -101,8 +101,24 @@ struct gfx_point {
     color_t rgb;
 };
 
+/*
+ * Represents a rectangular region on
+ * the screen.
+ *
+ * @x,y: Position of this region on the screen
+ * @width: Region width
+ * @heght: Region height
+ */
+struct gfx_region {
+    scrpos_t x, y;
+    dimm_t width;
+    dimm_t height;
+};
+
 int gfx_draw_shape(struct gfx_ctx *ctx, const struct gfx_shape *shape);
 int gfx_plot_point(struct gfx_ctx *ctx, const struct gfx_point *point);
+
+int gfx_copy_region(struct gfx_ctx *ctx, struct gfx_region *r, scrpos_t x, scrpos_t y);
 color_t gfx_get_pix(struct gfx_ctx *ctx, uint32_t x, uint32_t y);
 
 __always_inline static inline size_t
diff --git a/lib/libgfx/src/draw.c b/lib/libgfx/src/draw.c
index 784110a..43e0f08 100644
--- a/lib/libgfx/src/draw.c
+++ b/lib/libgfx/src/draw.c
@@ -182,3 +182,43 @@ gfx_draw_shape(struct gfx_ctx *ctx, const struct gfx_shape *shape)
 
     return -1;
 }
+
+/*
+ * Copy a region on one part of a screen to
+ * another part of a screen.
+ *
+ * @ctx: Graphics context pointer
+ * @r: Region to copy
+ * @x: X position for copy dest
+ * @y: Y position for copy dest
+ */
+int
+gfx_copy_region(struct gfx_ctx *ctx, struct gfx_region *r, scrpos_t x, scrpos_t y)
+{
+    struct gfx_point point;
+    color_t pixel;
+    scrpos_t src_cx, src_cy;
+    dimm_t w, h;
+
+    if (ctx == NULL || r == NULL) {
+        return -EINVAL;
+    }
+
+    w = r->width;
+    h = r->height;
+
+    for (int xoff = 0; xoff < w; ++xoff) {
+        for (int yoff = 0; yoff < h; ++yoff) {
+            /* Source position */
+            src_cx = r->x + xoff;
+            src_cy = r->y + yoff;
+
+            /* Plot the new pixel */
+            pixel = gfx_get_pix(ctx, src_cx, src_cy);
+            point.x = x + xoff;
+            point.y = y + yoff;
+            point.rgb = pixel;
+            gfx_plot_point(ctx, &point);
+        }
+    }
+}