Legacy ImageMagick Discussions Archive

I have a PNG with 1-bit color. I'm trying to resize it. Identify shows this for the original:

  Format: PNG (Portable Network Graphics)
  Class: PseudoClass
  Geometry: 180x192
  Type: Bilevel
  Endianess: Undefined
  Colorspace: Gray
  Channel depth:
    Gray: 1-bits
  Channel statistics:
    Gray:
      Min: 0 (0)
      Max: 1 (1)
      Mean: 0.596644 (0.596644)
      Standard deviation: 0.490571 (0.490571)
  Colors: 2

If I resize it like this:

Code: Select all

convert -resize x115 -depth 1 original.png smaller.png

The resulting file looks like this:

Code: Select all

  Format: PNG (Portable Network Graphics)
  Class: DirectClass
  Geometry: 108x115
  Type: Grayscale
  Endianess: Undefined
  Colorspace: Gray
  Channel depth:
    Gray: 8-bits
  Channel statistics:
    Gray:
      Min: 0 (0)
      Max: 255 (1)
      Mean: 152.01 (0.596119)
      Standard deviation: 116.442 (0.456636)
  Colors: 246

How do I resize the image while retaining 1-bit depth?

The correct order for commands is in the logical chronological order. In this case: read the image, resize it, set the depth, write it. Try that.

If you "resize" an image there are likely to be more colors in the output than in the input due to interpolation. Use "-sample" to avoid adding colors and
then you shouldn't need to specify the depth.

Legacy ImageMagick Discussions Archive

Resize PNG ignores specified depth

Resize PNG ignores specified depth

Re: Resize PNG ignores specified depth

Re: Resize PNG ignores specified depth