I have not fully understood what was going wrong, but I did discover that whenfig._get_renderer is called,fig.dpi gets reset to 72. As the renderer had deliberately set it to something elsehere, this is probably not helpful! Anyway, it is intuitive to me that the renderer used to work out where things are should be the same renderer that does this part of the drawing. Taking a simplified version of the#27763 example,

frommpl_toolkits.axes_grid1.inset_locatorimportinset_axesimportmatplotlib.pyplotaspltimportnumpyasnpfig,axes=plt.subplots(1,1,dpi=100)x=np.random.randint(100,size=(10,200))c=axes.imshow(x,origin='lower',cmap='Reds',aspect='auto')axins1=inset_axes(axes,width="10%",height="30%",loc="upper left",bbox_to_anchor= (0.045,0.,1,1),bbox_transform=axes.transAxes                    )fig.colorbar(c,cax=axins1,orientation="horizontal")fig.savefig('test_single.pdf',bbox_inches='tight')

With main:

With my branch:

The alignment is still not perfect (as also shown in the new test image), but it looks identical to what I get with v3.7.1 (before I started breaking things 🐑). I note that several commenters on the issue seemed happy with v3.7.1 behaviour. Also I cannot see any offset if I increase the dpi to 300:

I propose to open a new issue to track the remaining small offset.

PR checklist

"closes #0000" is in the body of the PR description tolink the related issue
new and changed code istested
[n/a]Plotting related features are demonstrated in anexample
[n/a]New Features andAPI Changes are noted with adirective and release note
[n/a] Documentation complies withgeneral anddocstring guidelines

FIX: pass renderer through adjust_bbox

0908973

github-actionsbot added topic: geometry manager

LayoutEngine, Constrained layout, Tight layout

topic: canvas and figure manager labels

Dec 17, 2024

rcomer commented

Dec 17, 2024

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lib/matplotlib/backend_bases.py

		@@ -2169,7 +2172,7 @@ def print_figure(

		# call adjust_bbox to save only the given area
		restore_bbox = _tight_bbox.adjust_bbox(
		self.figure, bbox_inches, self.figure.canvas.fixed_dpi)
		self.figure, bbox_inches,renderer,self.figure.canvas.fixed_dpi)

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rcomerDec 17, 2024•
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Passing the renderer here does not affect the target issue but I assume that passing it when we have it is more efficient than potentially calling_get_renderer again.

rcomer added the PR: bugfixPull requests that fix identified bugs label

Dec 17, 2024

timhoffm approved these changes

Dec 18, 2024

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jklymak approved these changes

Dec 18, 2024

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Is there a test we can do with the main library, or are the effects too subtle there?

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rcomer commentedDec 18, 2024•
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Is there a test we can do with the main library, or are the effects too subtle there?

We need an axes that uses a locator that requires a renderer. Do we have one of those in the main library? I checked thatAxes.inset_axes' locator works without a renderer.

Also I should have mentioned that this change does nothing for your example at#27763 (comment) (although that one also looks fine if you bump the dpi to 300).