When drawing markers, don't set the GraphicsContext alpha. #11105
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| ln_color_rgba = self._get_rgba_ln_color() | ||
| gc.set_foreground(ln_color_rgba, isRGBA=True) | ||
| gc.set_alpha(ln_color_rgba[3]) | ||
| lc_rgba = mcolors.to_rgba(self._color, self._alpha) |
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OK, so _alpha overrides the alpha in self._color if its not None. I'm confused if thats what happened before.
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Yes. As a general rule, an explicit alpha will override one that comes "with the color" (we can always discuss whether that's a good strategy (I think it's a mess) but that's what we have for now). The exception is the one noted in the comment re: markeredgecolor.
(Before, that happened via get_rgba_ln_color, which I had forgotten to remove but now did.)
Setting the alpha value on the GraphicsContext forcefully applies it to both the edgecolor and the facecolor, *except* that a facecolor of `None` ignores the alpha. Instead of requiring this behavior (which needlessly complicates the implementation of new rendering backends), the alpha value (if any) can directly be preapplied to the edgecolor and facecolor, the edgecolor can be applied using gc.set_foreground, and the alpha value never set on the GraphicsContext.
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| @@ -536,7 +536,10 @@ def draw_markers( | |||
| ps_cmd = ['/o {', 'gsave', 'newpath', 'translate'] # don't want the translate to be global | |||
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| lw = gc.get_linewidth() | |||
| stroke = lw != 0.0 | |||
| alpha = (gc.get_alpha() | |||
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This effectively treats alpha as a bool for ps?
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We do the same for text.
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There seem to be a conflict, please backport manually |
…-alpha
FIX: When drawing markers, don't set the GraphicsContext alpha.
Conflicts:
lib/matplotlib/lines.py
- keep aliases (which are implemented automatically on
master) explicitly in code
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backported to v2.2.x as 393c862 |
Setting the alpha value on the GraphicsContext forcefully applies it to
both the edgecolor and the facecolor, except that a facecolor of
Noneignores the alpha.Instead of requiring this behavior (which needlessly complicates the
implementation of new rendering backends), the alpha value (if any) can
directly be preapplied to the edgecolor and facecolor, the edgecolor can
be applied using gc.set_foreground, and the alpha value never set on the
GraphicsContext.
The change to backend_ps is necessary because we no longer artificially set the linewidth to zero for transparent markers to prevent drawing on the ps backend.
Fixes #11104. Milestoned as 2.2.3 as "fixes a regression".
Also (unintentionally) fixes the SVG part of #10035 (not sure for the pdf part, which may involve a ghostscript bug anyways); updated test images accordingly.
Part of the longstanding effort (#7430) to not have two conflicting sources of alpha...
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