[mgp-users 1506] Re: Problem with mgp2ps -c

[Kevin.Buckley@ecs.vuw.ac.nz]

> Another problem seems to be the implementation of newimage under mgp2ps.
> First, simple black and white graphics don't appear (I suspect that this
> is the same problem as above).

Just to say that I have recently seen a problem with newimage in
mgp itself, when loading a 16-bit image.

Using ImageMagick's identify on the PNG that fails and one that doesn't

$ identify kepler-uifilt-002d-75.png
kepler-uifilt-002d-75.png PNG 536x133 536x133+0+0 DirectClass 16-bit
69.6543kb


$ identify kepler-003-85-montage.png
kepler-003-85-montage.png PNG 799x417 799x417+0+0 DirectClass 16-bit
130.646kb

tells me little, however, when I add the verbose flag

Image: kepler-uifilt-002d-75.png
  Format: PNG (Portable Network Graphics)
  Class: DirectClass
  Geometry: 536x133+0+0
  Type: TrueColorMatte
  Endianess: Undefined
  Colorspace: RGB
  Depth: 16-bit
  Channel depth:
    Red: 16-bit
    Green: 16-bit
    Blue: 16-bit
    Alpha: 1-bit
  Channel statistics:
    Red:
      Min: 0 (0)
      Max: 65535 (1)
      Mean: 55133.3 (0.84128)
      Standard deviation: 14422.3 (0.220071)
    Green:
      Min: 0 (0)
      Max: 65535 (1)
      Mean: 55057.5 (0.840123)
      Standard deviation: 14480.2 (0.220954)
    Blue:
      Min: 0 (0)
      Max: 65535 (1)
      Mean: 53650 (0.818646)
      Standard deviation: 14696 (0.224247)
    Opacity:
      Min: 0 (0)
      Max: 0 (0)
      Mean: 0 (0)
      Standard deviation: 0 (0)
  Rendering intent: Undefined
  Resolution: 72x72
  Units: Undefined
  Filesize: 69.6543kb
  Interlace: None
  Background color: white
  Border color: rgb(223,223,223)
  Matte color: grey74
  Transparent color: none
  Page geometry: 536x133+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Zip
  Orientation: Undefined
  Properties:

Image: kepler-003-85-montage.png
  Format: PNG (Portable Network Graphics)
  Class: DirectClass
  Geometry: 799x417+0+0
  Type: TrueColor
  Endianess: Undefined
  Colorspace: RGB
  Depth: 8-bit
  Channel depth:
    Red: 8-bit
    Green: 8-bit
    Blue: 8-bit
  Channel statistics:
    Red:
      Min: 0 (0)
      Max: 255 (1)
      Mean: 221.074 (0.866959)
      Standard deviation: 64.3881 (0.252502)
    Green:
      Min: 0 (0)
      Max: 255 (1)
      Mean: 228.147 (0.894692)
      Standard deviation: 48.0718 (0.188517)
    Blue:
      Min: 0 (0)
      Max: 255 (1)
      Mean: 229.612 (0.900439)
      Standard deviation: 45.124 (0.176957)
  Rendering intent: Undefined
  Resolution: 72x72
  Units: Undefined
  Filesize: 130.646kb
  Interlace: None
  Background color: white
  Border color: rgb(223,223,223)
  Matte color: grey74
  Transparent color: black
  Page geometry: 799x417+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Zip
  Orientation: Undefined
  Properties:

it would seem that the one that fails has an explicit alpha
channel.

I have compiled versions of mgp that have rendered the image
in question correctly, in the past, so I am thinking that it
is something a bit deeper.

I am trying to dig deeper and will report any findings. I'd be
happy to hear of anyone else's too,
Kevin

-- 
Kevin M. Buckley                                  Room:  CO327
School of Engineering and                         Phone: +64 4 463 5971
 Computer Science
Victoria University of Wellington
New Zealand