I have tried this for a test, but it gives an error message. Am I doing something wrong?magick wrote:Use -define png:color-type=2. See http://www.imagemagick.org/script/comma ... php#define about the PNG defines.
Still doesn't work:magick wrote:Use -define png:color-type=2. See http://www.imagemagick.org/script/comma ... php#define about the PNG defines.
Their first try did not work because the image was grayscale. You have to prepare the image as mentioned in the "-define" documentation to be of a type that agrees with the requested output format. Use -type Truecolor to do that.
"identify" does not describe the input format, only the contents of the image. If it contains only black and white pixels, it's bilevel even if they are stored in the PNG file (or another format) as 16-bit RGB, 8-bit RGB, 8-bit GA, etc.
To find out what's really in the PNG file, use -debug coder or a 3rd-party app like pngcheck.
This works:
convert logo: -resize 50% -colorspace gray -transparent white logo2gt.png
convert logo2gt.png -type Truecolor -define png:color-type=6 logo2gt_t6.png
even doing this:This works:
convert logo: -resize 50% -colorspace gray -transparent white logo2gt.png
convert logo2gt.png -type Truecolor -define png:color-type=6 -debug coder logo2gt_t6.png
fmw42 wrote:even doing this:This works:
convert logo: -resize 50% -colorspace gray -transparent white logo2gt.png
convert logo2gt.png -type Truecolor -define png:color-type=6 -debug coder logo2gt_t6.png
convert logo: -resize 50% -colorspace gray -transparent white logo2gt.png
convert logo2gt.png -type TruecolorMatte -define png:color-type=6 logo2gt_t6.png
The type showing in identify is still grayscalematte and not truecolormatte.
So you say that identify is not adequate to really know? Is that correct? PNGCHECK is needed then?
Back to my original example:Normally, when a format supports different subformats such as grayscale and truecolor, the encoder will try to choose an efficient subformat. The -type option can be used to overrride this behavior. For example, to prevent a JPEG from being written in grayscale format even though only gray pixels are present, use 'convert bird.png -type TrueColor bird.jpg'.
magick wrote:Use this command to report details about a PNG image:
- identify -verbose -debug coder -log %e file.png
I tested it. It still does not work. Are you sure it's fixed. Here is the output from my console: http://pastie.org/799836.magick wrote:There is a patch in ImageMagick 6.5.9-1 Beta that should fix the problem you reported. You test it now if you download the release from ftp://ftp.imagemagick.org/pub/ImageMagick/beta.
This isn't working either:magick wrote:The PNG developer says "tell 'em we patched "-define" not "-type." See the ChangeLog in the source distribution.
