check whether libpng supports iTXt chunks (#1020)

strukturag · Nov 2, 2023 · 3b1f465 · 3b1f465
1 parent 2289041
commit 3b1f465
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diff --git a/examples/decoder_png.cc b/examples/decoder_png.cc
@@ -213,6 +213,7 @@ InputImage loadPNG(const char* filename, int output_bit_depth)
 
   // --- read XMP data
 
+#ifdef PNG_iTXt_SUPPORTED
   png_textp textPtr = nullptr;
   const png_uint_32 nTextChunks = png_get_text(png_ptr, info_ptr, &textPtr, nullptr);
   for (png_uint_32 i = 0; i < nTextChunks; i++, textPtr++) {
@@ -231,6 +232,7 @@ InputImage loadPNG(const char* filename, int output_bit_depth)
       }
     }
   }
+#endif
 
   int band = png_get_channels(png_ptr, info_ptr);
 

diff --git a/examples/encoder_png.cc b/examples/encoder_png.cc
@@ -134,6 +134,7 @@ bool PngEncoder::Encode(const struct heif_image_handle* handle,
 
   // --- write XMP metadata
 
+#ifdef PNG_iTXt_SUPPORTED
   // spec: https://raw.githubusercontent.com/adobe/xmp-docs/master/XMPSpecifications/XMPSpecificationPart3.pdf
   std::vector<uint8_t> xmp = get_xmp_metadata(handle);
   if (!xmp.empty()) {
@@ -156,6 +157,7 @@ bool PngEncoder::Encode(const struct heif_image_handle* handle,
     xmp_text.itxt_length = text_length;
     png_set_text(png_ptr, info_ptr, &xmp_text, 1);
   }
+#endif
 
   png_write_info(png_ptr, info_ptr);