* osc7: initial patch implementation
Closes#153
* osc7: avoid redundant use of realpath()
* osc7: fix styling
* Changing position of the OSC7_PATCH toggle in patches.def.h
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Co-authored-by: Bakkeby <bakkeby@gmail.com>
This fixes the current implementation, which does not delete an image if
an application first erases the image and then spawns a new transparent
image in its place. The reason it didn't work before was because the two
operations were handled at different stages in the rendering pipeline.
Old images are automatically deleted if a new image is spawned over
them. This prevents them from piling up and choking the terminal when
viewing animated gifs.
Now if you use the latest version of Chafa to view the gifs, it
will set the transparency attribute (P2=1) to all sixel images
regardless of whether they are transparent or not. This prevents the
auto-delete from working because if the image is transparent, we can't
delete any images behind it.
The solution is that since Chafa fills the animation frames with an
opaque black background color, we treat the images as non-transparent if
they don't have any transparent pixels. This keeps the auto-delete
running with the new Chafa.
Although the solution works now, it may not be a long-term solution.
In the current implementation, when text is written over an image, we
have to cut the entire text line out of the image, regardless of how
long the text is. It doesn't look good, but it was a design choice for
the following reasons:
1) To keep the sixel engine as fast as possible
2) Most applications do not write text on the images anyway
To bring the st terminal in line with other terminals that support
sixels, I have now improved the sixel renderer so that the images can
now have gaps, which allows the text to be printed inside the images.
The changes should not affect performance in normal cases. Only when the
renderer has to deal with the text there might be some performance hits
depending on how many gaps there are in the images.
Patch by Mikhail Kot <to@myrrc.dev>
With some modifications to behave more like xterm (see note below).
Example:
printf '\033[48;2;255:0:0mtest\n'
https://invisible-island.net/xterm/ctlseqs/ctlseqs.html
Some notes:
"CSI Pm m Character Attributes (SGR).
[...]
o xterm allows either colons (standard) or semicolons
(legacy) to separate the subparameters (but after the
first colon, colons must be used).
P2 selects how the terminal draws the background color.
P2 Meaning
0 or 2 (default) Pixel positions specified as 0 are set to the
current background color.
1 Pixel positions specified as 0 remain at their
current color.
Both modes are now supported.
Ref. https://www.vt100.net/docs/vt3xx-gp/chapter14.html
With this patch, st will reset its window title when an empty string is
given as the terminal title. For example:
printf "\033]0;\007"
Some applications, like termdown, expect this functionality. xterm
implements it, but it seems that most other terminal emulators don't.
In any case, I don't see why there should ever be a case where the st
window doesn't have a title property.
Ref.
https://git.suckless.org/st/commit/497a75638291454875ba1ec8d484c7f3d6f41d66.html
