Changeset 7020d1f in mainline for uspace/lib/ui/src/paint.c

Timestamp:

2021-02-01T10:53:48Z (4 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

f14a900

Parents:

d70dc1c4

git-author:

Jiri Svoboda <jiri@…> (2020-01-31 16:53:25)

git-committer:

Jiri Svoboda <jiri@…> (2021-02-01 10:53:48)

Message:

Radio button

Please don't ask me how I derived the formulae for circle midpoint
algorithm, it's been 8 years and I just don't remember.

File:

• uspace/lib/ui/src/paint.c (modified) (2 diffs)

uspace/lib/ui/src/paint.c

@@ -1 +1 @@
 /*
- * Copyright (c) 2020 Jiri Svoboda
+ * Copyright (c) 2021 Jiri Svoboda
  * All rights reserved.
  *
@@ -149 +149 @@
 }
 
+/** Paint filled circle vertical scanline.
+ *
+ * @param gc Graphic context
+ * @param center Coordinates of the center of the circle
+ * @param x X-coordinate of the scanline
+ * @param y0 Lowest Y coordinate of the scanline (inclusive)
+ * @param y1 Highest Y coordinate of the scanline (inclusive)
+ * @param part Which part(s) of cicle to paint
+ * @return EOK on success or an error code
+ */
+static errno_t ui_paint_fcircle_line(gfx_context_t *gc, gfx_coord2_t *center,
+    gfx_coord_t x, gfx_coord_t y0, gfx_coord_t y1, ui_fcircle_part_t part)
+{
+        gfx_rect_t rect;
+        gfx_rect_t trect;
+
+        rect.p0.x = x;
+        rect.p0.y = y0;
+        rect.p1.x = x + 1;
+        rect.p1.y = y1;
+
+        /* Clip to upper-left/lower-right half of circle, if required */
+
+        if ((part & ui_fcircle_upleft) == 0) {
+                if (rect.p0.y < -rect.p1.x)
+                        rect.p0.y = -rect.p1.x;
+        }
+
+        if ((part & ui_fcircle_lowright) == 0) {
+                if (rect.p1.y > -rect.p1.x)
+                        rect.p1.y = -rect.p1.x;
+        }
+
+        /* If coordinates are reversed, there is nothing to do */
+        if (rect.p1.y <= rect.p0.y)
+                return EOK;
+
+        gfx_rect_translate(center, &rect, &trect);
+
+        return gfx_fill_rect(gc, &trect);
+}
+
+/** Paint filled circle scanlines corresponding to octant point.
+ *
+ * Fills the four vertical scanlines lying between the eight reflections
+ * of a circle point.
+ *
+ * @param gc Graphic context
+ * @param center Coordinates of the center
+ * @param r Radius in pixels
+ * @param part Which part(s) of cicle to paint
+ * @return EOK on success or an error code
+ */
+static int ui_paint_fcircle_point(gfx_context_t *gc, gfx_coord2_t *center,
+    gfx_coord2_t *p, ui_fcircle_part_t part)
+{
+        errno_t rc;
+
+        rc = ui_paint_fcircle_line(gc, center, +p->x, -p->y, p->y + 1, part);
+        if (rc != EOK)
+                return rc;
+        rc = ui_paint_fcircle_line(gc, center, -p->x, -p->y, p->y + 1, part);
+        if (rc != EOK)
+                return rc;
+        rc = ui_paint_fcircle_line(gc, center, +p->y, -p->x, p->x + 1, part);
+        if (rc != EOK)
+                return rc;
+        rc = ui_paint_fcircle_line(gc, center, -p->y, -p->x, p->x + 1, part);
+        if (rc != EOK)
+                return rc;
+
+        return EOK;
+}
+
+/** Paint a filled circle.
+ *
+ * @param gc Graphic context
+ * @param center Coordinates of the center
+ * @param r Radius in pixels
+ * @param part Which part(s) of cicle to paint
+ * @return EOK on success or an error code
+ */
+errno_t ui_paint_filled_circle(gfx_context_t *gc, gfx_coord2_t *center,
+    gfx_coord_t r, ui_fcircle_part_t part)
+{
+        gfx_coord2_t p;
+        gfx_coord_t f;
+        errno_t rc;
+
+        /* Run through one octant using circle midpoint algorithm */
+
+        p.x = r;
+        p.y = 0;
+        f = 1 - r;
+
+        rc = ui_paint_fcircle_point(gc, center, &p, part);
+        if (rc != EOK)
+                return rc;
+
+        while (p.x > p.y) {
+                if (f < 0) {
+                        f = f + 2 * p.y + 3;
+                } else {
+                        f = f + 2 * (p.y - p.x) + 5;
+                        --p.x;
+                }
+                ++p.y;
+
+                rc = ui_paint_fcircle_point(gc, center, &p, part);
+                if (rc != EOK)
+                        return rc;
+        }
+
+        return EOK;
+}
+
 /** @}
  */