test: Add a compile-time check in pngimage.c to avoid a failure

Disable the check on `interlace_method` inside function `compare_read` in pngimage.c, if WRITE_INTERLACING is not supported. If interlaced encoding is disabled inside libpng, the encoded images are non-interlaced silently and unconditionally. This commit updates the image comparison to skip the interlace check in the resultant image; other behavior is still checked. Reviewed-by: Cosmin Truta <[email protected]> Signed-off-by: John Bowler <[email protected]> Signed-off-by: Cosmin Truta <[email protected]>
pnggroup · Oct 15, 2024 · d9f13d8 · d9f13d8
1 parent f45531c
commit d9f13d8
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/contrib/libtests/pngimage.c b/contrib/libtests/pngimage.c
@@ -1016,7 +1016,12 @@ compare_read(struct display *dp, int applied_transforms)
    C(height);
    C(bit_depth);
    C(color_type);
-   C(interlace_method);
+#  ifdef PNG_WRITE_INTERLACING_SUPPORTED
+      /* If write interlace has been disabled, the PNG file is still
+       * written correctly, but as a regular (not-interlaced) PNG.
+       */
+      C(interlace_method);
+#  endif
    C(compression_method);
    C(filter_method);