feat(obj): add transform matrix attribute (#7187)

tests/src/test_cases/widgets/test_obj_transform.c

@@ -0,0 +1,62 @@
+#if LV_BUILD_TEST
+#include "../lvgl.h"
+#include "unity/unity.h"
+
+void setUp(void)
+{
+    /* Function run before every test */
+}
+
+void tearDown(void)
+{
+    /* Function run after every test */
+    lv_obj_clean(lv_screen_active());
+}
+
+void test_obj_transform(void)
+{
+#if LV_DRAW_TRANSFORM_USE_MATRIX
+    lv_obj_t * obj = lv_obj_create(lv_screen_active());
+    lv_obj_set_size(obj, 100, 100);
+    lv_obj_center(obj);
+
+    lv_matrix_t matrix;
+
+    lv_matrix_identity(&matrix);
+    lv_obj_set_transform(obj, &matrix);
+    TEST_ASSERT_EQUAL_SCREENSHOT("widgets/obj_transform_identity.png");
+
+    lv_matrix_identity(&matrix);
+    lv_matrix_translate(&matrix, 50, 100);
+    lv_obj_set_transform(obj, &matrix);
+    TEST_ASSERT_EQUAL_SCREENSHOT("widgets/obj_transform_translate.png");
+
+    lv_matrix_identity(&matrix);
+    lv_matrix_rotate(&matrix, 30);
+    lv_obj_set_transform(obj, &matrix);
+    TEST_ASSERT_EQUAL_SCREENSHOT("widgets/obj_transform_rotate.png");
+
+    lv_matrix_identity(&matrix);
+    lv_matrix_scale(&matrix, 0.8f, 1.6f);
+    lv_obj_set_transform(obj, &matrix);
+    TEST_ASSERT_EQUAL_SCREENSHOT("widgets/obj_transform_scale.png");
+
+    lv_matrix_identity(&matrix);
+    lv_matrix_skew(&matrix, 10.0f, 20.0f);
+    lv_obj_set_transform(obj, &matrix);
+    TEST_ASSERT_EQUAL_SCREENSHOT("widgets/obj_transform_skew.png");
+
+    const lv_matrix_t * obj_transform = lv_obj_get_transform(obj);
+    TEST_ASSERT_NOT_NULL(obj_transform);
+    TEST_ASSERT_EQUAL(lv_memcmp(&matrix, obj_transform, sizeof(lv_matrix_t)), 0);
+
+    lv_obj_reset_transform(obj);
+    TEST_ASSERT_EQUAL_SCREENSHOT("widgets/obj_transform_identity.png");
+    TEST_ASSERT_NULL(lv_obj_get_transform(obj));
+
+#else
+    TEST_PASS();
+#endif
+}
+
+#endif