Index: uspace/lib/ui/private/testgc.h
===================================================================
--- uspace/lib/ui/private/testgc.h	(revision 0dab4850c8601c3ffb2cf910cb99650e1766ff26)
+++ uspace/lib/ui/private/testgc.h	(revision 0dab4850c8601c3ffb2cf910cb99650e1766ff26)
@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2022 Jiri Svoboda
+ * Copyright (c) 2025 Jiří Zárevúcky
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+typedef struct {
+	bool bm_created;
+	bool bm_destroyed;
+	gfx_bitmap_params_t bm_params;
+	void *bm_pixels;
+	gfx_rect_t bm_srect;
+	gfx_coord2_t bm_offs;
+	bool bm_rendered;
+	bool bm_got_alloc;
+} test_gc_t;
+
+typedef struct {
+	test_gc_t *tgc;
+	gfx_bitmap_alloc_t alloc;
+	bool myalloc;
+} testgc_bitmap_t;
+
+static errno_t testgc_set_clip_rect(void *arg, gfx_rect_t *rect)
+{
+	(void) arg;
+	(void) rect;
+	return EOK;
+}
+
+static errno_t testgc_set_color(void *arg, gfx_color_t *color)
+{
+	(void) arg;
+	(void) color;
+	return EOK;
+}
+
+static errno_t testgc_fill_rect(void *arg, gfx_rect_t *rect)
+{
+	(void) arg;
+	(void) rect;
+	return EOK;
+}
+
+static errno_t testgc_update(void *arg)
+{
+	(void) arg;
+	return EOK;
+}
+
+static errno_t testgc_bitmap_create(void *arg, gfx_bitmap_params_t *params,
+    gfx_bitmap_alloc_t *alloc, void **rbm)
+{
+	test_gc_t *tgc = (test_gc_t *) arg;
+	testgc_bitmap_t *tbm;
+
+	tbm = calloc(1, sizeof(testgc_bitmap_t));
+	if (tbm == NULL)
+		return ENOMEM;
+
+	if (alloc == NULL) {
+		tbm->alloc.pitch = (params->rect.p1.x - params->rect.p0.x) *
+		    sizeof(uint32_t);
+		tbm->alloc.off0 = 0;
+		tbm->alloc.pixels = calloc(
+		    (params->rect.p1.x - params->rect.p0.x) *
+		    (params->rect.p1.y - params->rect.p0.y),
+		    sizeof(uint32_t));
+		tbm->myalloc = true;
+		if (tbm->alloc.pixels == NULL) {
+			free(tbm);
+			return ENOMEM;
+		}
+	} else {
+		tbm->alloc = *alloc;
+	}
+
+	tbm->tgc = tgc;
+	tgc->bm_created = true;
+	tgc->bm_params = *params;
+	tgc->bm_pixels = tbm->alloc.pixels;
+	*rbm = (void *)tbm;
+	return EOK;
+}
+
+static errno_t testgc_bitmap_destroy(void *bm)
+{
+	testgc_bitmap_t *tbm = (testgc_bitmap_t *)bm;
+	if (tbm->myalloc)
+		free(tbm->alloc.pixels);
+	tbm->tgc->bm_destroyed = true;
+	free(tbm);
+	return EOK;
+}
+
+static errno_t testgc_bitmap_render(void *bm, gfx_rect_t *srect,
+    gfx_coord2_t *offs)
+{
+	testgc_bitmap_t *tbm = (testgc_bitmap_t *)bm;
+	tbm->tgc->bm_rendered = true;
+	tbm->tgc->bm_srect = *srect;
+	tbm->tgc->bm_offs = *offs;
+	return EOK;
+}
+
+static errno_t testgc_bitmap_get_alloc(void *bm, gfx_bitmap_alloc_t *alloc)
+{
+	testgc_bitmap_t *tbm = (testgc_bitmap_t *)bm;
+	*alloc = tbm->alloc;
+	tbm->tgc->bm_got_alloc = true;
+	return EOK;
+}
+
+static gfx_context_ops_t ops = {
+	.set_clip_rect = testgc_set_clip_rect,
+	.set_color = testgc_set_color,
+	.fill_rect = testgc_fill_rect,
+	.update = testgc_update,
+	.bitmap_create = testgc_bitmap_create,
+	.bitmap_destroy = testgc_bitmap_destroy,
+	.bitmap_render = testgc_bitmap_render,
+	.bitmap_get_alloc = testgc_bitmap_get_alloc
+};