| Type: | Package |
| Title: | Convert Png Files into Animated Png |
| Version: | 1.1 |
| Date: | 2021-01-12 |
| Author: | Quinten Stokkink |
| Maintainer: | Quinten Stokkink <q.a.stokkink@tudelft.nl> |
| Depends: | bitops |
| Description: | Convert several png files into an animated png file. This package exports only a single function ‘apng’. Call the apng function with a vector of file names (which should be png files) to convert them to a single animated png file. |
| License: | GPL-3 | file LICENSE |
| NeedsCompilation: | no |
| Packaged: | 2021-01-12 20:57:30 UTC; quinten |
| Repository: | CRAN |
| Date/Publication: | 2021-01-13 10:50:28 UTC |
Convert Png Files into Animated Png
Description
Convert several png files into an animated png file. This package exports only a single function ‘apng’. Call the apng function with a vector of file names (which should be png files) to convert them to a single animated png file.
Note
The CRC implementation in this package was adopted from the W3 Portable Network Graphics (PNG) Specification (Second Edition): Annex D - Sample Cyclic Redundancy Code implementation. As such, special thanks go out to the authors of the specification: https://www.w3.org/TR/PNG/#F-Relationship.
Author(s)
Quinten Stokkink
Maintainer: Quinten Stokkink <q.a.stokkink@tudelft.nl>
References
https://www.w3.org/TR/PNG/
https://wiki.mozilla.org/APNG_Specification
Blend previous frame into alpha
Description
When rendering a new frame, the previous frame is filled into the alpha of the new frame. For example, 50% red over blue makes purple.
Value
1
Completely replace the previous frame
Description
When rendering a new frame, the region is filled as specified exactly by the new frame. For example, 50% red over blue makes 50% red over the background.
Value
0
Prepare region as fully transparent
Description
Before a new frame is rendered, the region is replaced by the background color.
Value
1
Write over the current output buffer
Description
Nothing is done to the existing buffer when a new frame is rendered.
Value
0
Keep previous frame in rendering region
Description
Before a new frame is rendered, the region is restored to what it was before the previous frame.
Value
2
Convert static pngs to animated png
Description
Combine multiple png files into an animated png file.
Usage
apng(input_files = c(), output_file = "output.png",
num_plays = 0, delay_num = 0, delay_den = 0,
dispose_op = APNG_DISPOSE_OP_NONE,
blend_op = APNG_BLEND_OP_SOURCE)
Arguments
input_files |
to specify the names of the input files |
output_file |
the name of the output file |
num_plays |
the amount of times to repeat the animation (0 means forever) |
delay_num |
the numerator of the frame delay ( |
delay_den |
the denominator of the frame delay ( |
dispose_op |
the frame disposal strategy |
blend_op |
the frame blending strategy |
For more information on blending and frame disposal strategies see https://wiki.mozilla.org/APNG_Specification.
Value
Returns nothing, output is written to output_file.
Examples
input1 <- tempfile(pattern = "", fileext = ".png")
input2 <- tempfile(pattern = "", fileext = ".png")
output <- tempfile(pattern = "", fileext = ".png")
# Generate inputs.
png(filename=input1)
plot(1:40, (1:40)^2)
dev.off()
png(filename=input2)
plot(1:40, (-1*1:40)^3)
dev.off()
# Create an animated png.
apng(c(input1, input2), output)