From d66cf61aad92e7e544fff5538f1b656b462fc8ca Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Mon, 23 Jan 2023 11:55:02 +0300
Subject: [PATCH] stb_image.h: sync with mainstream dev branch.
---
stb_image.h | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/stb_image.h b/stb_image.h
index 2e9210be..c8cfaeb6 100644
--- a/stb_image.h
+++ b/stb_image.h
@@ -5199,14 +5199,13 @@ static int stbi__parse_png_file(stbi__png *z, int scan, int req_comp)
if (!pal_img_n) {
s->img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0);
if ((1 << 30) / s->img_x / s->img_n < s->img_y) return stbi__err("too large", "Image too large to decode");
- if (scan == STBI__SCAN_header) return 1;
} else {
// if paletted, then pal_n is our final components, and
// img_n is # components to decompress/filter.
s->img_n = 1;
if ((1 << 30) / s->img_x / 4 < s->img_y) return stbi__err("too large","Corrupt PNG");
- // if SCAN_header, have to scan to see if we have a tRNS
}
+ // even with SCAN_header, have to scan to see if we have a tRNS
break;
}
@@ -5238,6 +5237,8 @@ static int stbi__parse_png_file(stbi__png *z, int scan, int req_comp)
if (!(s->img_n & 1)) return stbi__err("tRNS with alpha","Corrupt PNG");
if (c.length != (stbi__uint32) s->img_n*2) return stbi__err("bad tRNS len","Corrupt PNG");
has_trans = 1;
+ // non-paletted with tRNS = constant alpha. if header-scanning, we can stop now.
+ if (scan == STBI__SCAN_header) { ++s->img_n; return 1; }
if (z->depth == 16) {
for (k = 0; k < s->img_n; ++k) tc16[k] = (stbi__uint16)stbi__get16be(s); // copy the values as-is
} else {
@@ -5250,7 +5251,12 @@ static int stbi__parse_png_file(stbi__png *z, int scan, int req_comp)
case STBI__PNG_TYPE('I','D','A','T'): {
if (first) return stbi__err("first not IHDR", "Corrupt PNG");
if (pal_img_n && !pal_len) return stbi__err("no PLTE","Corrupt PNG");
- if (scan == STBI__SCAN_header) { s->img_n = pal_img_n; return 1; }
+ if (scan == STBI__SCAN_header) {
+ // header scan definitely stops at first IDAT
+ if (pal_img_n)
+ s->img_n = pal_img_n;
+ return 1;
+ }
if (c.length > (1u << 30)) return stbi__err("IDAT size limit", "IDAT section larger than 2^30 bytes");
if ((int)(ioff + c.length) < (int)ioff) return 0;
if (ioff + c.length > idata_limit) {