png driver: support for .bmp files?

[hamish]

Hi,

it would seem that the grass7 version of the PNG driver can create .bmp files if you pass it GRASS_PNGFILE=filename.bmp, and so you can use it with ximgview, but the pngdriver man page doesn't mention this.

?

is this feature available in 6.x?

Hamish

[glynn]

Replying to hamish:

it would seem that the grass7 version of the PNG driver can create .bmp files if you pass it GRASS_PNGFILE=filename.bmp, and so you can use it with ximgview, but the pngdriver man page doesn't mention this. ?

is this feature available in 6.x?

Yes. All versions of the PNG and cairo drivers support PNG, PPM/PGM and BMP files, except that the cairo driver only supports PNG files if cairo itself was built with PNG support (which is usually the case).

Note that they only supports 32-bpp BMP files, which not all image viewers support. The reason is so that the drivers can mmap() the BMP file and use the mapped region (minus the header) as the frame buffer (which must be 32-bpp), rather than needing to explicitly read/write the file (when mapping a BMP file, the header is ignored).

[hamish]

driver docs updated, all branches.