v1.8.0

Added

• ImageEngine.RegionCacheBytes (default 64 MiB per frame, 0 = off) and Image.ReleaseDecodedPixels(): repeated CopyPixelsTo region reads (bands, random rectangles) of a large JPEG or PNG no longer decode the image again. See the guide's pixel-access section.

Changed

• Region reads of large JPEG/PNG frames: from the second region read on, the rows read are kept in a plane in the requested pixel format (at most RegionCacheBytes per frame, released by ReleaseDecodedPixels() or when the image is collected). Reading 44 Gray8 bands or 20 random rectangles of an A4 page now costs about one decode instead of up to three, and a rotated (EXIF) image no longer restarts decoding for each output row. The price is memory: a Gray8 plane of an A4 page is about 8.7 MB and an Rgb24 plane about 26 MB, kept while the image is alive. Set RegionCacheBytes = 0 for the previous behaviour. Pixel values are unchanged.
• The first Image.Load of a PNG or JPEG costs less resident memory (about +2.5 MB instead of +6 to +11 MB): the header parsers are split so the JIT compiles small methods instead of one large one.