test(draw_buf): add draw buf premultiply test (#9259)

Signed-off-by: rongyichang <rongyichang@xiaomi.com>
2026-05-21 22:52:46 +08:00 · 2025-11-20 11:15:59 +08:00
parent fc345314f8
commit d40474645b
1 changed files with 142 additions and 0 deletions
@@ -127,4 +127,146 @@ void test_draw_buf_xy_access(void)
    TEST_ASSERT_NULL(ret);
 }

+
+void test_draw_buf_premultiply(void)
+{
+    lv_draw_buf_t * draw_buf;
+    lv_result_t res;
+    int i;
+    /* Test ARGB8888 format */
+    {
+        draw_buf = lv_draw_buf_create(2, 2, LV_COLOR_FORMAT_ARGB8888, 2 * 4);
+
+        /* Fill with test data: white with 50% alpha */
+        lv_color32_t * pixel = (lv_color32_t *)draw_buf->data;
+        for(i = 0; i < 4; i++) {
+            pixel[i] = (lv_color32_t) {
+                .alpha = 128, .red = 255, .green = 255, .blue = 255
+            };
+        }
+
+        res = lv_draw_buf_premultiply(draw_buf);
+        TEST_ASSERT_EQUAL(LV_RESULT_OK, res);
+        TEST_ASSERT(draw_buf->header.flags & LV_IMAGE_FLAGS_PREMULTIPLIED);
+
+        /* Verify premultiplied result: color should be 127 = (255 * 128) >> 8, alpha should be 128 */
+        for(i = 0; i < 4; i++) {
+            TEST_ASSERT_EQUAL_UINT8(127, pixel[i].red);
+            TEST_ASSERT_EQUAL_UINT8(127, pixel[i].green);
+            TEST_ASSERT_EQUAL_UINT8(127, pixel[i].blue);
+            TEST_ASSERT_EQUAL_UINT8(128, pixel[i].alpha); /* Alpha should remain unchanged */
+        }
+
+        lv_draw_buf_destroy(draw_buf);
+    }
+
+    /* Test XRGB8888 format */
+    {
+        draw_buf = lv_draw_buf_create(2, 2, LV_COLOR_FORMAT_XRGB8888, 2 * 4);
+
+        /* Fill with test data: white with 50% alpha */
+        lv_color32_t * pixel = (lv_color32_t *)draw_buf->data;
+        for(i = 0; i < 4; i++) {
+            pixel[i] = (lv_color32_t) {
+                .alpha = 255, .red = 255, .green = 255, .blue = 255
+            };
+        }
+
+        res = lv_draw_buf_premultiply(draw_buf);
+        TEST_ASSERT_EQUAL(LV_RESULT_INVALID, res); /* XRGB8888 is not supported */
+
+        lv_draw_buf_destroy(draw_buf);
+    }
+
+    /* Test RGB565A8 format */
+    {
+        draw_buf = lv_draw_buf_create(2, 2, LV_COLOR_FORMAT_RGB565A8, 2 * 2);
+
+        /* Fill with test data */
+        uint16_t * pixel = (uint16_t *)draw_buf->data;
+        lv_opa_t * alpha = (lv_opa_t *)(draw_buf->data + 2 * 2 * 2); /* RGB565 data size */
+        for(i = 0; i < 4; i++) {
+            pixel[i] = lv_color_to_u16(lv_color_white()); /* White: 0xFFFF in RGB565 */
+            alpha[i] = 128; /* 50% alpha */
+        }
+
+        res = lv_draw_buf_premultiply(draw_buf);
+        TEST_ASSERT_EQUAL(LV_RESULT_OK, res);
+        TEST_ASSERT(draw_buf->header.flags & LV_IMAGE_FLAGS_PREMULTIPLIED);
+
+        /* Verify premultiplied result: white (0xFFFF) with 50% alpha should become gray */
+        for(i = 0; i < 4; i++) {
+            /* RGB565: 5-6-5 bits, white premultiplied by 0.5 should be approximately half intensity */
+            TEST_ASSERT_EQUAL_UINT16(0x7BEF, pixel[i]); /* Approximate half of white in RGB565 */
+        }
+
+        lv_draw_buf_destroy(draw_buf);
+    }
+
+    /* Test ARGB8565 format */
+    {
+        draw_buf = lv_draw_buf_create(2, 2, LV_COLOR_FORMAT_ARGB8565, 2 * 3);
+
+        /* Fill with test data */
+        uint8_t * pixel = draw_buf->data;
+        for(i = 0; i < 4; i++) {
+            uint16_t c = lv_color_to_u16(lv_color_white()); /* White: 0xFFFF */
+            pixel[0] = c & 0xFF;         /* Low byte of RGB565 */
+            pixel[1] = (c >> 8) & 0xFF;  /* High byte of RGB565 */
+            pixel[2] = 128;                   /* Alpha */
+            pixel += 3;
+        }
+
+        res = lv_draw_buf_premultiply(draw_buf);
+        TEST_ASSERT_EQUAL(LV_RESULT_OK, res);
+        TEST_ASSERT(draw_buf->header.flags & LV_IMAGE_FLAGS_PREMULTIPLIED);
+
+        /* Verify premultiplied result */
+        pixel = draw_buf->data;
+        for(i = 0; i < 4; i++) {
+            uint16_t c = (pixel[1] << 8) | pixel[0]; /* Reconstruct RGB565 */
+            /* White premultiplied by 0.5 should be approximately half intensity */
+            TEST_ASSERT_EQUAL_UINT16(0x7BEF, c); /* Approximate half of white in RGB565 */
+            TEST_ASSERT_EQUAL_UINT8(128, pixel[2]); /* Alpha should remain unchanged */
+            pixel += 3;
+        }
+
+        lv_draw_buf_destroy(draw_buf);
+    }
+
+    /* Test indexed format (I1/I2/I4/I8) */
+    lv_color_format_t color_formats[] = {
+        LV_COLOR_FORMAT_I1,
+        LV_COLOR_FORMAT_I2,
+        LV_COLOR_FORMAT_I4,
+        LV_COLOR_FORMAT_I8,
+    };
+
+    for(unsigned int fmt_i = 0; fmt_i < sizeof(color_formats) / sizeof(color_formats[0]); fmt_i++) {
+        draw_buf = lv_draw_buf_create(2, 2, color_formats[fmt_i], 0);
+
+        /* Fill palette with test data */
+        lv_color32_t * palette = (lv_color32_t *)draw_buf->data;
+        int palette_size = LV_COLOR_INDEXED_PALETTE_SIZE(color_formats[fmt_i]);
+        for(i = 0; i < palette_size; i++) {
+            palette[i] = (lv_color32_t) {
+                .alpha = 128, .red = 255, .green = 255, .blue = 255
+            };
+        }
+
+        res = lv_draw_buf_premultiply(draw_buf);
+        TEST_ASSERT_EQUAL(LV_RESULT_OK, res);
+        TEST_ASSERT(draw_buf->header.flags & LV_IMAGE_FLAGS_PREMULTIPLIED);
+
+        /* Verify palette was premultiplied */
+        for(i = 0; i < palette_size; i++) {
+            TEST_ASSERT_EQUAL_UINT8(127, palette[i].red);
+            TEST_ASSERT_EQUAL_UINT8(127, palette[i].green);
+            TEST_ASSERT_EQUAL_UINT8(127, palette[i].blue);
+            TEST_ASSERT_EQUAL_UINT8(128, palette[i].alpha);
+        }
+
+        lv_draw_buf_destroy(draw_buf);
+    }
+}
 #endif