int im_png2vips( const char *filename, IMAGE *out )
int im_vips2png( IMAGE *in, const char *filename )
im_vips2png(3) reads the image in and writes a PNG file to the specified filename. The filename may include an optional mode string, following a ':' character, which you can use to specify compression and interlace.
The mode string has the following syntax:
<compression>,<interlace>
where <compression> is an integer between 0 and 9 specifying the amount of compression (6 is the default), and <interlace> is 0 for no interlace (this is the default) and 1 for ADAM7 interlace.
Beware that writing an interlaced image is potentially up to 7 times slower than writing a non-interlaced image.
The image is automatically converted to RGB or Monochrome (with an optional alpha channel) before saving.
The call:
im_vips2png fred.v fred.png
Writes a compression 6, uninterlaced PNG image.
im_vips2png fred.v fred.tif:,1
Writes an interlaced image.