Skip to content

Fix the variable transparency case that was broken by the #8255 commit. #8612

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
joa-quim merged 1 commit into from
Nov 9, 2024
Merged

Fix the variable transparency case that was broken by the #8255 commit. #8612

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 9 additions & 6 deletions doc/rst/source/grdimage.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ Synopsis
[ |-I|\ [*file*\|\ *intens*\|\ **+a**\ *azimuth*][**+d**][**+m**\ *ambient*][**+n**\ *args*] ]
[ |-M| ]
[ |-N| ]
[ |-Q|\ [*color*][**+i**][**+z**\ *value*] ]
[ |-Q|\ [*color*][**+i**][**+t**][**+z**\ *value*] ]
[ |SYN_OPT-Rz| ]
[ |-T|\ [**+o**\ [*pen*]][**+s**] ]
[ |SYN_OPT-U| ]
Expand Down Expand Up @@ -158,7 +158,7 @@ Optional Arguments

.. _-Q:

**-Q**\ [*color*][**+i**][**+z**\ *value*]
**-Q**\ [*color*][**+i**][**+t**][**+z**\ *value*]
Handle transparency or opacity for grids or images. There are four general schemes:

- Grid - Plain |-Q| will turn grid nodes with NaN values transparent in the image, using
Expand All @@ -173,10 +173,13 @@ Optional Arguments
transparency between 0 and 255 on a per pixel basis then the *PostScript* image operator
cannot create true variable pixel transparency *t*. Instead, each *r*, *g*, and *b* pixel
values are converted by :math:`r' = t R + (1-t) r`, where *R* (and *G*, *B*) is the
transparent color at full transparency [Default is white]. If *color* is given
then it becomes the *R*, *B*, *G* at full transparency. Such RGBA images will
be approximated by *n_columns* times *n_rows* of tiny squares with variable color and
transparency. If *A* reflects opacity instead of transparency then you can use modifier
transparent color at full transparency [Default is white]. If *color* is given then it
becomes the *R*, *B*, *G* at full transparency. This (opaque) transformation is
actually done by default (_i.e._, no need to set **-Q**). If, however, a true transparency
is wished, then use the **+i** modifier. Such RGBA images will be approximated by *n_columns*
times *n_rows* of tiny squares with variable color and transparency. Given this schema, the
PositScript created file is much larger than if **+t** is not used and that is why this is
not the default behavior. If *A* reflects opacity instead of transparency then you can use modifier
**+i** to invert these numbers first. See `Limitations on transparency`_ for more discussion.
**Note**: The **+i** modifier is not available for grids.

Expand Down