Title: | Graphic Devices Based on AGG |
---|---|
Description: | Anti-Grain Geometry (AGG) is a high-quality and high-performance 2D drawing library. The 'ragg' package provides a set of graphic devices based on AGG to use as alternative to the raster devices provided through the 'grDevices' package. |
Authors: | Thomas Lin Pedersen [cre, aut] , Maxim Shemanarev [aut, cph] (Author of AGG), Tony Juricic [ctb, cph] (Contributor to AGG), Milan Marusinec [ctb, cph] (Contributor to AGG), Spencer Garrett [ctb] (Contributor to AGG), Posit, PBC [cph, fnd] |
Maintainer: | Thomas Lin Pedersen <[email protected]> |
License: | MIT + file LICENSE |
Version: | 1.3.3.9000 |
Built: | 2024-11-10 02:58:51 UTC |
Source: | https://github.com/r-lib/ragg |
Usually the point of using a graphic device is to create a file or show the
graphic on the screen. A few times we need the image data for further
processing in R, and instead of writing it to a file and then reading it back
into R the agg_capture()
device lets you get the image data directly from
the buffer. In contrast to the other devices this device returns a function,
that when called will return the current state of the buffer.
agg_capture( width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, bg )
agg_capture( width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, bg )
width , height
|
The dimensions of the device |
units |
The unit |
pointsize |
The default pointsize of the device in pt. This will in general not have any effect on grid graphics (including ggplot2) as text size is always set explicitly there. |
background |
The background colour of the device |
res |
The resolution of the device. This setting will govern how device dimensions given in inches, centimeters, or millimeters will be converted to pixels. Further, it will be used to scale text sizes and linewidths |
scaling |
A scaling factor to apply to the rendered line width and text
size. Useful for getting the right dimensions at the resolution that you
need. If e.g. you need to render a plot at 4000x3000 pixels for it to fit
into a layout, but you find that the result appears to small, you can
increase the |
snap_rect |
Should axis-aligned rectangles drawn with only fill snap to the pixel grid. This will prevent anti-aliasing artifacts when two rectangles are touching at their border. |
bg |
Same as |
A function that when called returns the current state of the buffer.
The return value of the function depends on the native
argument. If FALSE
(default) the return value is a matrix
of colour values and if TRUE
the
return value is a nativeRaster
object.
cap <- agg_capture() plot(1:10, 1:10) # Get the plot as a matrix raster <- cap() # Get the plot as a nativeRaster raster_n <- cap(native = TRUE) dev.off() # Look at the output plot(as.raster(raster))
cap <- agg_capture() plot(1:10, 1:10) # Get the plot as a matrix raster <- cap() # Get the plot as a nativeRaster raster_n <- cap(native = TRUE) dev.off() # Look at the output plot(as.raster(raster))
The JPEG file format is a lossy compressed file format developed in
particular for digital photography. The format is not particularly
well-suited for line drawings and text of the type normally associated with
statistical plots as the compression algorithm creates noticable artefacts.
It is, however, great for saving image data, e.g. heightmaps etc. Thus, for
standard plots, it would be better to use agg_png()
, but for plots that
includes a high degree of raster image rendering this device will result in
smaller plots with very little quality degradation.
agg_jpeg( filename = "Rplot%03d.jpeg", width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, quality = 75, smoothing = FALSE, method = "slow", bg )
agg_jpeg( filename = "Rplot%03d.jpeg", width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, quality = 75, smoothing = FALSE, method = "slow", bg )
filename |
The name of the file. Follows the same semantics as the file
naming in |
width , height
|
The dimensions of the device |
units |
The unit |
pointsize |
The default pointsize of the device in pt. This will in general not have any effect on grid graphics (including ggplot2) as text size is always set explicitly there. |
background |
The background colour of the device |
res |
The resolution of the device. This setting will govern how device dimensions given in inches, centimeters, or millimeters will be converted to pixels. Further, it will be used to scale text sizes and linewidths |
scaling |
A scaling factor to apply to the rendered line width and text
size. Useful for getting the right dimensions at the resolution that you
need. If e.g. you need to render a plot at 4000x3000 pixels for it to fit
into a layout, but you find that the result appears to small, you can
increase the |
snap_rect |
Should axis-aligned rectangles drawn with only fill snap to the pixel grid. This will prevent anti-aliasing artifacts when two rectangles are touching at their border. |
quality |
An integer between |
smoothing |
A smoothing factor to apply before compression, from |
method |
The compression algorithm to use. Either |
bg |
Same as |
Smoothing is only applied if ragg has been compiled against a jpeg library that supports smoothing.
file <- tempfile(fileext = '.jpeg') agg_jpeg(file, quality = 50) plot(sin, -pi, 2*pi) dev.off()
file <- tempfile(fileext = '.jpeg') agg_jpeg(file, quality = 50) plot(sin, -pi, 2*pi) dev.off()
The PNG (Portable Network Graphic) format is one of the most ubiquitous
today, due to its versatiliity
and widespread support. It supports transparency as well as both 8 and 16 bit
colour. The device uses default compression and filtering and will not use a
colour palette as this is less useful for antialiased data. This means that
it might be possible to compress the resulting image even more if size is of
concern (though the defaults are often very good). In contrast to
grDevices::png()
the date and time will not be written to the file, meaning
that similar plot code will produce identical files (a good feature if used
with version control). It will, however, write in the dimensions of the image
based on the res
argument.
agg_png( filename = "Rplot%03d.png", width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, bitsize = 8, bg )
agg_png( filename = "Rplot%03d.png", width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, bitsize = 8, bg )
filename |
The name of the file. Follows the same semantics as the file
naming in |
width , height
|
The dimensions of the device |
units |
The unit |
pointsize |
The default pointsize of the device in pt. This will in general not have any effect on grid graphics (including ggplot2) as text size is always set explicitly there. |
background |
The background colour of the device |
res |
The resolution of the device. This setting will govern how device dimensions given in inches, centimeters, or millimeters will be converted to pixels. Further, it will be used to scale text sizes and linewidths |
scaling |
A scaling factor to apply to the rendered line width and text
size. Useful for getting the right dimensions at the resolution that you
need. If e.g. you need to render a plot at 4000x3000 pixels for it to fit
into a layout, but you find that the result appears to small, you can
increase the |
snap_rect |
Should axis-aligned rectangles drawn with only fill snap to the pixel grid. This will prevent anti-aliasing artifacts when two rectangles are touching at their border. |
bitsize |
Should the device record colour as 8 or 16bit |
bg |
Same as |
file <- tempfile(fileext = '.png') agg_png(file) plot(sin, -pi, 2*pi) dev.off()
file <- tempfile(fileext = '.png') agg_png(file) plot(sin, -pi, 2*pi) dev.off()
The PPM (Portable Pixel Map) format defines one of the simplest storage formats available for image data. It is basically a raw 8bit RGB stream with a few bytes of information in the start. It goes without saying, that this file format is horribly inefficient and should only be used if you want to play around with a simple file format, or need a file-based image stream.
agg_ppm( filename = "Rplot%03d.ppm", width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, bg )
agg_ppm( filename = "Rplot%03d.ppm", width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, bg )
filename |
The name of the file. Follows the same semantics as the file
naming in |
width , height
|
The dimensions of the device |
units |
The unit |
pointsize |
The default pointsize of the device in pt. This will in general not have any effect on grid graphics (including ggplot2) as text size is always set explicitly there. |
background |
The background colour of the device |
res |
The resolution of the device. This setting will govern how device dimensions given in inches, centimeters, or millimeters will be converted to pixels. Further, it will be used to scale text sizes and linewidths |
scaling |
A scaling factor to apply to the rendered line width and text
size. Useful for getting the right dimensions at the resolution that you
need. If e.g. you need to render a plot at 4000x3000 pixels for it to fit
into a layout, but you find that the result appears to small, you can
increase the |
snap_rect |
Should axis-aligned rectangles drawn with only fill snap to the pixel grid. This will prevent anti-aliasing artifacts when two rectangles are touching at their border. |
bg |
Same as |
file <- tempfile(fileext = '.ppm') agg_ppm(file) plot(sin, -pi, 2*pi) dev.off()
file <- tempfile(fileext = '.ppm') agg_ppm(file) plot(sin, -pi, 2*pi) dev.off()
The TIFF (Tagged Image File Format) format is a very versatile raster image storage format that supports 8 and 16bit colour mode, true transparency, as well as a range of other features not relevant to drawing from R (e.g. support for different colour spaces). The storage mode of the image data is not fixed and different compression modes are possible, in contrast to PNGs one-approach-fits-all. The default (uncompressed) will result in much larger files than PNG, and in general PNG is a better format for many of the graphic types produced in R. Still, TIFF has its purposes and sometimes this file format is explicetly requested.
agg_tiff( filename = "Rplot%03d.tiff", width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, compression = "none", bitsize = 8, bg )
agg_tiff( filename = "Rplot%03d.tiff", width = 480, height = 480, units = "px", pointsize = 12, background = "white", res = 72, scaling = 1, snap_rect = TRUE, compression = "none", bitsize = 8, bg )
filename |
The name of the file. Follows the same semantics as the file
naming in |
width , height
|
The dimensions of the device |
units |
The unit |
pointsize |
The default pointsize of the device in pt. This will in general not have any effect on grid graphics (including ggplot2) as text size is always set explicitly there. |
background |
The background colour of the device |
res |
The resolution of the device. This setting will govern how device dimensions given in inches, centimeters, or millimeters will be converted to pixels. Further, it will be used to scale text sizes and linewidths |
scaling |
A scaling factor to apply to the rendered line width and text
size. Useful for getting the right dimensions at the resolution that you
need. If e.g. you need to render a plot at 4000x3000 pixels for it to fit
into a layout, but you find that the result appears to small, you can
increase the |
snap_rect |
Should axis-aligned rectangles drawn with only fill snap to the pixel grid. This will prevent anti-aliasing artifacts when two rectangles are touching at their border. |
compression |
The compression type to use for the image data. The
standard options from the |
bitsize |
Should the device record colour as 8 or 16bit |
bg |
Same as |
TIFF have support for true transparency, meaning that the pixel colour is stored in pre-multiplied form. This is in contrast to pixels being stored in plain format, where the alpha values more function as a mask. The utility of this is not always that important, but it is one of the benefits of TIFF over PNG so it should be noted.
'jpeg'
compression is only available if ragg is compiled with a
version of libtiff
where jpeg support has been turned on.
file <- tempfile(fileext = '.tiff') # Use jpeg compression agg_tiff(file, compression = 'lzw+p') plot(sin, -pi, 2*pi) dev.off()
file <- tempfile(fileext = '.tiff') # Use jpeg compression agg_tiff(file, compression = 'lzw+p') plot(sin, -pi, 2*pi) dev.off()