gradient-convert - Man Page

gradient-convert [-b rgb] [-B] [-c] [-f rgb] [-g geometry] [-G] [-h] [-i format] [-n rgb] [-o format] [-p] [-T rgb] [-v] [-V] [-z] [-4] [-5] [-6] infile outfile

The gradient-convert program converts gradients to other formats​. It is a wrapper script which make a number of calls the individual programs from the cptutils package so, for example, to convert a GMT colour palette (cpt) to a PNG image, the programs cptsvg and svgpng would be called in sequence to generate the required file​.

The formats of the mandatory infile and outfile arguments are determined from the file extensions, or can be specified explicitly by the -i and -o options​.

In the following, all rgb specifications should be of the form red/green/blue where the colour components are integers in the range 0 to 255​.

-b,  --background rgb

Set the background colour of cpt output​.

Note that this only modifies the "background" field in the output cpt file, it does not affect the transparency (see the --transparency option in that regard)​.

--backtrace-file path

Specify a file to which to write a formatted backtrace​. The file will only be created if there is a backtrace created, typically when an error occurs​.

--backtrace-format format

Specify the format of the backtrace written to the files specified by --backtrace-file, one of plain, xml or json​.

-B,  --burst

Some of the file formats handled by cptutils may contain multiple gradients: the Photoshop (grd) and SVG formats for example​. By default, the program will extract only the first gradient from such files; but when the --burst option is selected then all gradients will be extracted​. In this case the outfile argument must be a directory (and that directory should already exist)​.

-c,  --capabilities

Print the capabilities of the program to stdout​. This data (in YAML format) may be used to autoconfigure other programs which wish to use this program​. The format should be self-explanatory​.

-f,  --foreground rgb

Set the foreground colour of cpt output​.

-g,  --geometry widthxheight

Specify the size of the PNG image or SVG preview in pixels​.

-G,  --graphviz

Print the conversion graph to stdout in the GraphViz dot format​. See dot(1) for details on creating a plot of the graph from this output​.

-h,  --help

Brief help​.

-i,  --input-format format

Specify the format of the input file​. Run the program with the --help option for a list of supported formats​.

-n,  --nan rgb

Set the NaN (no data) colour of cpt output​.

-o,  --output-format format

Specify the format of the output file​. Run the program with the --help option for a list of supported formats​.

-p,  --preview

Include a preview in the SVG output​. See also the --geometry option​.

-T,  --transparency rgb

When converting to a format which does not support transparency, replace the transparency with the specified rgb colour​.

-v,  --verbose

Verbose operation​.

-V,  --version

Version information​.

-z,  --zip

For input formats which may contain multiple gradients (grd, svg) the --zip extracts all of the gradients and zips them up​. Thus it can be viewed as similar to the burst option (--burst)​. The zipfile to be created should be the final argument and when unzipped it will create a directory (containing the converted gradients) with the same name as the file with the ​.zip extension removed​.

-4,  --gmt4

Use GMT 4 conventions when writing the cpt output: the colour-model code is uppercase, and the colours are separated by spaces​.

This is incompatible with the -5 and -6 options of course​.

At present this option is the default, but that will change at some point​. So specify this option if your use of the output depends on the GMT 4 layout (consumed by a custom parser, for example)​.

-5,  --gmt5

Use GMT 5 conventions when writing the cpt output: the colour-model code is lowercase, and the colours are separated by a solidus for RGB, CMYK, by a dash for HSV​.

This is incompatible with the -4 and -6 options of course​.

-6,  --gmt6

As the -5 option, but allows the HARD_HINGE and SOFT_HINGE directives in place of the explicit HINGE = directive​.

This is incompatible with the -4 and -5 options of course​.

Convert a GMT colour palette to a 200×20 pixel PNG image:

gradient-convert -v -g 200x20 legend​.cpt legend​.png

Convert all gradients in a Photoshop gradient to GMT cpt files in a zipfile:

gradient-convert -v -i grd -o cpt -z froob​.grd froob​.zip

The component programs in the conversion will generally have a number of options available for modifying the conversion behaviour, but only the most-often used of these options can be passed to component programs from gradient-convert​.

Note also that those options which are passed to component programs are not checked for relevance​. Converting a GMT cpt file to GIMP format while using using the irrelevant --geometry option will not cause an error, it will simply be ignored​.

J​.J​. Green