Add Unit tests for clipping functions

coresdk/src/test/unit_tests/unit_test_clipping.cpp

@@ -0,0 +1,102 @@
+/**
+ * Clipping Unit Tests
+ * 
+ * 
+ * Created by Matthew Sutrisno
+ */
+
+#include "graphics.h"
+#include "color.h"
+#include "catch.hpp"
+
+using namespace splashkit_lib;
+
+
+static bool pixel_is(bitmap bmp, int x, int y, color expected)
+{
+    color c = get_pixel(bmp, x, y);
+
+    return (red_of(c) == red_of(expected) &&
+            green_of(c) == green_of(expected) &&
+            blue_of(c) == blue_of(expected) &&
+            alpha_of(c) == alpha_of(expected));
+}
+
+TEST_CASE("set_clip restricts drawing to area", "[graphics][clipping]")
+{
+    bitmap bmp = create_bitmap("clip_test1", 40, 40);
+    clear_bitmap(bmp, COLOR_WHITE);
+
+    set_clip(bmp, rectangle_from(10, 10, 20, 20));
+
+    fill_rectangle(COLOR_RED, 0, 0, 40, 40, option_draw_to(bmp));
+
+    REQUIRE(pixel_is(bmp, 15, 15, COLOR_RED));
+
+    REQUIRE(pixel_is(bmp, 5, 5, COLOR_WHITE));
+    REQUIRE(pixel_is(bmp, 35, 35, COLOR_WHITE));
+
+    free_bitmap(bmp);
+}
+
+TEST_CASE("push_clip intersects clipping regions", "[graphics][clipping]")
+{
+    bitmap bmp = create_bitmap("clip_test2", 40, 40);
+    clear_bitmap(bmp, COLOR_WHITE);
+
+    set_clip(bmp, rectangle_from(10, 10, 20, 20));
+
+    push_clip(bmp, rectangle_from(20, 0, 10, 40));
+
+    fill_rectangle(COLOR_BLUE, 0, 0, 40, 40, option_draw_to(bmp));
+
+    REQUIRE(pixel_is(bmp, 25, 15, COLOR_BLUE));
+
+    REQUIRE(pixel_is(bmp, 15, 15, COLOR_WHITE));
+
+    REQUIRE(pixel_is(bmp, 5, 5, COLOR_WHITE));
+
+    free_bitmap(bmp);
+}
+
+TEST_CASE("pop_clip restores previous clipping region", "[graphics][clipping]")
+{
+    bitmap bmp = create_bitmap("clip_test3", 40, 40);
+    clear_bitmap(bmp, COLOR_WHITE);
+
+    set_clip(bmp, rectangle_from(5, 5, 20, 20));
+
+    push_clip(bmp, rectangle_from(10, 10, 20, 20));
+
+    fill_rectangle(COLOR_GREEN, 0, 0, 40, 40, option_draw_to(bmp));
+
+    REQUIRE(pixel_is(bmp, 12, 12, COLOR_GREEN));
+    REQUIRE(pixel_is(bmp, 6, 6, COLOR_WHITE));
+
+    pop_clip(bmp);
+
+    fill_rectangle(COLOR_RED, 0, 0, 40, 40, option_draw_to(bmp));
+
+    REQUIRE(pixel_is(bmp, 6, 6, COLOR_RED));
+
+    REQUIRE(pixel_is(bmp, 30, 30, COLOR_WHITE));
+
+    free_bitmap(bmp);
+}
+
+TEST_CASE("reset_clip removes clipping", "[graphics][clipping]")
+{
+    bitmap bmp = create_bitmap("clip_test4", 40, 40);
+    clear_bitmap(bmp, COLOR_WHITE);
+
+    set_clip(bmp, rectangle_from(10, 10, 10, 10));
+
+    reset_clip(bmp);
+
+    fill_rectangle(COLOR_GOLD, 0, 0, 40, 40, option_draw_to(bmp));
+
+    REQUIRE(pixel_is(bmp, 0, 0, COLOR_GOLD));
+    REQUIRE(pixel_is(bmp, 39, 39, COLOR_GOLD));
+
+    free_bitmap(bmp);
+}