问题
android version upgrade to 5.x, I got a png image through screenshot. when I use imagemagick to resize it, I got an error like this
identify: Extra compressed data. `a.png' @ warning/png.c/MagickPNGWarningHandler/1777.
identify: Extra compression data. `a.png' @ warning/png.c/MagickPNGWarningHandler/1777.
convert: Extra compressed data. `a.png' @ warning/png.c/MagickPNGWarningHandler/1777.
convert: Extra compression data. `a.png' @ warning/png.c/MagickPNGWarningHandler/1777.
use pngcheck info:
File: a.png (251221 bytes)
chunk IHDR at offset 0x0000c, length 13
1440 x 2560 image, 24-bit RGB, non-interlaced
chunk sBIT at offset 0x00025, length 3
red = 8 = 0x08, green = 8 = 0x08, blue = 8 = 0x08
chunk IDAT at offset 0x00034, length 251149
zlib: deflated, 32K window, maximum compression
chunk IEND at offset 0x3d54d, length 0
No errors detected in a.png (4 chunks, 97.7% compression).
My soft version: ImageMagick 6.7.9-0 PNG* PNG rw- Portable Network Graphics (libpng 1.2.52) See http://www.libpng.org/ for details about the PNG format. PNG24* PNG rw- opaque 24-bit RGB (zlib 1.2.8,1.2.1.2)
I tryed ImageMagick-6.9.1-6 and libpng-1.6.17 zlib-1.2.8, all are newest version, but got error yet
please try this png image , and help me...
http://pan.baidu.com/s/1mg3mkCo
thanks
回答1:
"Extra compressed data" is just a warning. You may ignore it.
The result of your "convert" operation should be OK; ImageMagick won't propagate the extra data.
Note that "pngcheck" doesn't decompress the IDAT chunks so it won't report about the extra data that is evidently due to a bug in the screenshot application.
回答2:
Add the option -quiet to your convert or identify command so you don't get an error generated.
来源：https://stackoverflow.com/questions/31139824/png-imagemagick-error-extra-compressed-data