From ff3f2a9d8490381047920173a563dcdd30efa700 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Sat, 25 Mar 2023 01:43:22 -0700
Subject: [PATCH] Util: Strip loading 16-bit PNGs down to 8-bit

---
 src/util/png-io.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/src/util/png-io.c b/src/util/png-io.c
index 6c25f399c..80c7a9d7c 100644
--- a/src/util/png-io.c
+++ b/src/util/png-io.c
@@ -279,6 +279,14 @@ bool PNGReadPixels(png_structp png, png_infop info, void* pixels, unsigned width
 		return false;
 	}
 
+	if (png_get_bit_depth(png, info) == 16) {
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+		png_set_scale_16(png);
+#else
+		png_set_strip_16(png);
+#endif
+	}
+
 	uint8_t* pixelData = pixels;
 	unsigned pngHeight = png_get_image_height(png, info);
 	if (height < pngHeight) {
@@ -334,6 +342,14 @@ bool PNGReadPixelsA(png_structp png, png_infop info, void* pixels, unsigned widt
 		return false;
 	}
 
+	if (png_get_bit_depth(png, info) == 16) {
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+		png_set_scale_16(png);
+#else
+		png_set_strip_16(png);
+#endif
+	}
+
 	uint8_t* pixelData = pixels;
 	unsigned pngHeight = png_get_image_height(png, info);
 	if (height < pngHeight) {
@@ -389,6 +405,14 @@ bool PNGReadPixels8(png_structp png, png_infop info, void* pixels, unsigned widt
 		return false;
 	}
 
+	if (png_get_bit_depth(png, info) == 16) {
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+		png_set_scale_16(png);
+#else
+		png_set_strip_16(png);
+#endif
+	}
+
 	uint8_t* pixelData = pixels;
 	unsigned pngHeight = png_get_image_height(png, info);
 	if (height < pngHeight) {