Workstation Types

The layered architecture of GR and GKS allows the use of a wide variety of GUI toolkits and file formats using so-called workstations. You can select the workstation by setting the GKS_WSTYPE environment variable or by explicitly opening it using gks_openws(). These workstation types will also be used when you print the output to a file using gr_beginprint(), GR.beginprint(pathname), gr.beginprint() or mlab.savefig().

File Formats

Plugin	GKS_WSTYPE	File Type
built-in	pdf / 102	PDF
built-in	ps / 62	PS
built-in	eps / 62	EPS
videoplugin	gif / 130	GIF
videoplugin	mov / 120	MOV
videoplugin	mov / 121	HiDPI MOV
videoplugin	mp4 / 160	MP4
videoplugin	webm / 161	WEBM
videoplugin	ogg / 162	OGG
cairoplugin	bmp / 145	BMP
gsplugin	bmp / 320	BMP
aggplugin	ppm / 170	PPM
cairoplugin	jpg / jpeg / 144	JPEG
gsplugin	jpg / jpeg / 321	JPEG
aggplugin	jpg / jpeg / 172	JPEG
cairoplugin	png / 140	PNG
gsplugin	png / 322	PNG
aggplugin	png / 171	PNG
cairoplugin	tif / tiff / 146	TIFF
gsplugin	tif / tiff / 323	TIFF
figplugin	fig / 370	FIG
svgplugin	svg / 382	SVG
wmfplugin	wmf / 390	WMF
htmplugin	html / 430	HTML
pgfplugin	pgf / 314	TEX

Both the cairoplugin and the gsplugin can be used to create PNG, JPEG, BMP and TIFF files. PNG and JPEG files can be created by the aggplugin as well. If it is available, the cairoplugin will be used by default, but the environment variables GKS_USE_GS_PNG, GKS_USE_GS_JPG, GKS_USE_GS_BMP or GKS_USE_GS_TIF can be set to use the gsplugin and GKS_USE_AGG_PNG or GKS_USE_AGG_JPG can be set to use the aggplugin instead.

Configuring Video Output Options

The video files generated by the videoplugin have a default resolution of 720 x 720 pixels at 24 frames per second. You can change those values by setting the GKS_VIDEO_OPTS environment variable to one of the following values:

• <framerate>

• <width>x<height>

• <width>x<height>@<framerate>

mov video files can additionally be generated in HiDPI mode if supported by ffmpeg. This doubles the internal resolution while using the given resolution for playback size in supporting video players (primarily Apple QuickTime). To enable HiDPI mode for mov videos either use the GKS_WSTYPE 121 or append @x2 to the GKS_VIDEO_OPTS, for example:

• 1920x1080@60@x2

Integrations

Plugin	GKS_WSTYPE	Description
qtplugin	381	Qt 4
qt5plugin	381	Qt 5
qt6plugin	381	Qt 6
gtkplugin	371	GTK+
wxplugin	380	wxWidgets
glplugin	420	OpenGL

By default the Qt-plugins use Qt’s internal drawing functions. This behavior can be changed to use either cairo or agg to render the image by setting the environment variables GKS_QT_USE_CAIRO or GKS_QT_USE_AGG.

Applications

Application	Plugin	GKS_WSTYPE	Operating System
gksqt	qt5plugin	411 / gksqt	Windows / Linux / macOS
GKSTerm	quartzplugin	400 / quartz	macOS
GKS 5 (X11)	x11plugin	211 / x11	Linux / macOS
GKS 5 (Windows)	built-in	41	Windows

Special Workstation Types

No Output

To use GR without generating output, you can use workstation type 100. You will still be able to explicitly write output to a file using gr_beginprint() or similar GR functions, but there will be no implicit output to an application or file.

Memory

To write an image directly to memory as 32-bit RGBA data, you can allocate the memory and then use a specially constructed filename with the format !<width>x<height>@<pointer>.mem using hexadecimal notation for the pointer, e.g. by passing it to gr_beginprint(). Once GR has finished writing the image, e.g. after calling gr_endprint(), the memory will contain the image data.

# Allocate image memory, e.g. using numpy
import numpy as np
width, height = 1920, 1080
image = np.zeros((height, width, 4), np.uint8)
pointer = image.ctypes.data

# Draw something into the memory using gr
import gr
gr.beginprint('!{}x{}@{:x}.mem'.format(width, height, pointer))
gr.polyline([0, 1], [0, 1])
gr.endprint()

# Use the image memory, e.g. using PIL/pillow
from PIL import Image
image = Image.fromarray(image, 'RGBA')
# ...

/* Allocate image memory */
int width = 1920;
int height = 1080;
unsigned char *data = malloc(height * width * 4);

/* Draw something into the memory using GR */
double x[] = {0, 1};
double y[] = {0, 1};
char filename[32];
sprintf(filename, "!%dx%d@%p.mem", width, height, data);
gr_beginprint(filename);
gr_polyline(2, x, y);
gr_endprint();

/* Use the image memory and free it afterwards */
/* ... */
free(data);