minui: Add support for ARGB (LSB alpha)
- Called RGBA to follow convention in minui
where big-endian description of format is used
and to avoid conflict with existing ARGB
- Handle alpha being LSB in png and text rendering
Change-Id: I0d9afef55aad05028ed0b8b4204f1d52aaa683c3
(cherry picked from commit cd1c327427febe7cf76e6fa4835847f0d4f398e3)
diff --git a/minui/graphics.cpp b/minui/graphics.cpp
index f25694a..370b4cf 100644
--- a/minui/graphics.cpp
+++ b/minui/graphics.cpp
@@ -36,7 +36,6 @@
static int overscan_offset_y = 0;
static uint32_t gr_current = ~0;
-static constexpr uint32_t alpha_mask = 0xff000000;
// gr_draw is owned by backends.
static GRSurface* gr_draw = nullptr;
@@ -79,7 +78,7 @@
}
// Blends gr_current onto pix value, assumes alpha as most significant byte.
-static inline uint32_t pixel_blend(uint8_t alpha, uint32_t pix) {
+static inline uint32_t pixel_blend_argb(uint8_t alpha, uint32_t pix) {
if (alpha == 255) return gr_current;
if (alpha == 0) return pix;
uint32_t pix_r = pix & 0xff;
@@ -96,6 +95,48 @@
return (out_r & 0xff) | (out_g & 0xff00) | (out_b & 0xff0000) | (gr_current & 0xff000000);
}
+static inline uint32_t pixel_blend_rgba(uint8_t alpha, uint32_t pix) {
+ if (alpha == 255) return gr_current;
+ if (alpha == 0) return pix;
+ uint32_t pix_r = pix & 0xff00;
+ uint32_t pix_g = pix & 0xff0000;
+ uint32_t pix_b = pix & 0xff000000;
+ uint32_t cur_r = gr_current & 0xff00;
+ uint32_t cur_g = gr_current & 0xff0000;
+ uint32_t cur_b = gr_current & 0xff000000;
+
+ uint32_t out_r = (pix_r * (255 - alpha) + cur_r * alpha) / 255;
+ uint32_t out_g = (pix_g * (255 - alpha) + cur_g * alpha) / 255;
+ uint32_t out_b = (pix_b * (255 - alpha) + cur_b * alpha) / 255;
+
+ return (gr_current & 0xff) | (out_r & 0xff00) | (out_g & 0xff0000) | (out_b & 0xff000000);
+}
+
+static inline uint32_t pixel_blend(uint8_t alpha, uint32_t pix) {
+ if (pixel_format == PixelFormat::RGBA) {
+ return pixel_blend_rgba(alpha, pix);
+ }
+ return pixel_blend_argb(alpha, pix);
+}
+
+static inline uint32_t get_alphamask() {
+ if (pixel_format == PixelFormat::RGBA) {
+ return 0x000000ff;
+ }
+ return 0xff000000;
+}
+
+static inline uint8_t get_alpha_shift() {
+ if (pixel_format == PixelFormat::RGBA) {
+ return 0;
+ }
+ return 24;
+}
+
+static inline uint8_t get_alpha(uint32_t pix) {
+ return static_cast<uint8_t>((pix & (gr_current & get_alphamask())) >> get_alpha_shift());
+}
+
// Increments pixel pointer right, with current rotation.
static void incr_x(uint32_t** p, int row_pixels) {
if (rotation == GRRotation::LEFT) {
@@ -143,7 +184,7 @@
static void TextBlend(const uint8_t* src_p, int src_row_bytes, uint32_t* dst_p, int dst_row_pixels,
int width, int height) {
- uint8_t alpha_current = static_cast<uint8_t>((alpha_mask & gr_current) >> 24);
+ uint8_t alpha_current = get_alpha(gr_current);
for (int j = 0; j < height; ++j) {
const uint8_t* sx = src_p;
uint32_t* px = dst_p;
@@ -158,7 +199,7 @@
}
void gr_text(const GRFont* font, int x, int y, const char* s, bool bold) {
- if (!font || !font->texture || (gr_current & alpha_mask) == 0) return;
+ if (!font || !font->texture || (gr_current & get_alphamask()) == 0) return;
if (font->texture->pixel_bytes != 1) {
printf("gr_text: font has wrong format\n");
@@ -213,6 +254,8 @@
uint32_t r32 = r, g32 = g, b32 = b, a32 = a;
if (pixel_format == PixelFormat::ARGB || pixel_format == PixelFormat::BGRA) {
gr_current = (a32 << 24) | (r32 << 16) | (g32 << 8) | b32;
+ } else if (pixel_format == PixelFormat::RGBA) {
+ gr_current = (b32 << 24) | (g32 << 16) | (r32 << 8) | a32;
} else {
gr_current = (a32 << 24) | (b32 << 16) | (g32 << 8) | r32;
}
@@ -247,7 +290,7 @@
int row_pixels = gr_draw->row_bytes / gr_draw->pixel_bytes;
uint32_t* p = PixelAt(gr_draw, x1, y1, row_pixels);
- uint8_t alpha = static_cast<uint8_t>(((gr_current & alpha_mask) >> 24));
+ uint8_t alpha = get_alpha(gr_current);
if (alpha > 0) {
for (int y = y1; y < y2; ++y) {
uint32_t* px = p;
@@ -369,6 +412,8 @@
pixel_format = PixelFormat::ARGB;
} else if (format == "BGRA_8888") {
pixel_format = PixelFormat::BGRA;
+ } else if (format == "RGBA_8888") {
+ pixel_format = PixelFormat::RGBA;
} else {
pixel_format = PixelFormat::UNKNOWN;
}