shithub: rgbds

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Fix reading interlaced PNGs

Either we let libpng handle the transform, or we don't.
But make up your mind!

--- a/src/gfx/process.cpp

+++ b/src/gfx/process.cpp

@@ -294,8 +294,7 @@

 			png_set_packing(png);

 		}

-		// Set interlace handling (MUST be done before `png_read_update_info`)

-		int nbPasses = png_set_interlace_handling(png);

+		// Do NOT call `png_set_interlace_handling`. We want to expand the rows ourselves.

 		// Update `info` with the transformations

 		png_read_update_info(png, info);

@@ -323,8 +322,10 @@

 				}

 			}

 		} else {

+			assert(interlaceType == PNG_INTERLACE_ADAM7);

+

 			// For interlace to work properly, we must read the image `nbPasses` times

-			for (int pass = 0; pass < nbPasses; ++pass) {

+			for (int pass = 0; pass < PNG_INTERLACE_ADAM7_PASSES; ++pass) {

 				// The interlacing pass must be skipped if its width or height is reported as zero

 				if (PNG_PASS_COLS(width, pass) == 0 || PNG_PASS_ROWS(height, pass) == 0) {

 					continue;