From 886b6b365b6c91e9b60c89970f44be4c38de12f3 Mon Sep 17 00:00:00 2001
From: Hermet Park <hermet@lottiefiles.com>
Date: Wed, 7 Feb 2024 11:54:07 +0900
Subject: [PATCH] loaders: decode the image with premultiplied alpha.

basically, the renderer requires images with premultiplied alpha.
---
 src/loaders/external_png/tvgPngLoader.cpp   | 1 +
 src/loaders/external_webp/tvgWebpLoader.cpp | 3 +--
 src/loaders/png/tvgPngLoader.cpp            | 4 +++-
 src/loaders/webp/dec/webp.cpp               | 2 +-
 src/loaders/webp/tvgWebpLoader.cpp          | 2 +-
 5 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/loaders/external_png/tvgPngLoader.cpp b/src/loaders/external_png/tvgPngLoader.cpp
index 10277f84..95651afb 100644
--- a/src/loaders/external_png/tvgPngLoader.cpp
+++ b/src/loaders/external_png/tvgPngLoader.cpp
@@ -104,6 +104,7 @@ bool PngLoader::read()
     surface.h = (uint32_t)h;
     surface.channelSize = sizeof(uint32_t);
     surface.cs = ColorSpace::ARGB8888;
+    //TODO: we can acquire a pre-multiplied image. See "png_structrp"
     surface.premultiplied = false;
 
     clear();
diff --git a/src/loaders/external_webp/tvgWebpLoader.cpp b/src/loaders/external_webp/tvgWebpLoader.cpp
index e7fafdbb..46842b5e 100644
--- a/src/loaders/external_webp/tvgWebpLoader.cpp
+++ b/src/loaders/external_webp/tvgWebpLoader.cpp
@@ -33,9 +33,8 @@
 
 void WebpLoader::run(unsigned tid)
 {
+    //TODO: acquire the current colorspace format & pre-multiplied alpha image.
     surface.buf8 = WebPDecodeBGRA(data, size, nullptr, nullptr);
-
-    //setup the surface
     surface.stride = (uint32_t)w;
     surface.w = (uint32_t)w;
     surface.h = (uint32_t)h;
diff --git a/src/loaders/png/tvgPngLoader.cpp b/src/loaders/png/tvgPngLoader.cpp
index c8920dce..45d68124 100644
--- a/src/loaders/png/tvgPngLoader.cpp
+++ b/src/loaders/png/tvgPngLoader.cpp
@@ -44,7 +44,9 @@ void PngLoader::run(unsigned tid)
     surface.w = width;
     surface.h = height;
     surface.channelSize = sizeof(uint32_t);
-    surface.premultiplied = false;
+
+    if (state.info_png.color.colortype == LCT_RGBA) surface.premultiplied = false;
+    else surface.premultiplied = true;
 }
 
 
diff --git a/src/loaders/webp/dec/webp.cpp b/src/loaders/webp/dec/webp.cpp
index 7f6a5a44..df0d61f7 100644
--- a/src/loaders/webp/dec/webp.cpp
+++ b/src/loaders/webp/dec/webp.cpp
@@ -651,7 +651,7 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
 
 uint8_t* WebPDecodeBGRA(const uint8_t* data, size_t data_size,
                         int* width, int* height) {
-  return Decode(MODE_BGRA, data, data_size, width, height, NULL);
+  return Decode(MODE_bgrA, data, data_size, width, height, NULL);
 }
 
 
diff --git a/src/loaders/webp/tvgWebpLoader.cpp b/src/loaders/webp/tvgWebpLoader.cpp
index c9a7eb62..68c75c55 100644
--- a/src/loaders/webp/tvgWebpLoader.cpp
+++ b/src/loaders/webp/tvgWebpLoader.cpp
@@ -42,7 +42,7 @@ void WebpLoader::run(unsigned tid)
     surface.h = static_cast<uint32_t>(h);
     surface.cs = ColorSpace::ARGB8888;
     surface.channelSize = sizeof(uint32_t);
-    surface.premultiplied = false;
+    surface.premultiplied = true;
 
     clear();
 }