Merge pull request #28506 from meeseeksmachine/auto-backport-of-pr-28…

…451-on-v3.9.x

Backport PR #28451 on branch v3.9.x (Fix GTK cairo backends)

lib/matplotlib/backends/backend_gtk3cairo.py

@@ -13,15 +13,19 @@ def on_draw_event(self, widget, ctx):
 
  with (self.toolbar._wait_cursor_for_draw_cm() if self.toolbar
  else nullcontext()):
- self._renderer.set_context(ctx)
- scale = self.device_pixel_ratio
- # Scale physical drawing to logical size.
- ctx.scale(1 / scale, 1 / scale)
  allocation = self.get_allocation()
+ # Render the background before scaling, as the allocated size here is in
+ # logical pixels.
  Gtk.render_background(
  self.get_style_context(), ctx,
- allocation.x, allocation.y,
- allocation.width, allocation.height)
+ 0, 0, allocation.width, allocation.height)
+ scale = self.device_pixel_ratio
+ # Scale physical drawing to logical size.
+ ctx.scale(1 / scale, 1 / scale)
+ self._renderer.set_context(ctx)
+ # Set renderer to physical size so it renders in full resolution.
+ self._renderer.width = allocation.width * scale
+ self._renderer.height = allocation.height * scale
  self._renderer.dpi = self.figure.dpi
  self.figure.draw(self._renderer)
 

lib/matplotlib/backends/backend_gtk4.py

@@ -34,7 +34,6 @@ class FigureCanvasGTK4(_FigureCanvasGTK, Gtk.DrawingArea):
  required_interactive_framework = "gtk4"
  supports_blit = False
  manager_class = _api.classproperty(lambda cls: FigureManagerGTK4)
- _context_is_scaled = False
 
  def __init__(self, figure=None):
  super().__init__(figure=figure)
@@ -228,13 +227,8 @@ def _post_draw(self, widget, ctx):
 
  lw = 1
  dash = 3
- if not self._context_is_scaled:
- x0, y0, w, h = (dim / self.device_pixel_ratio
- for dim in self._rubberband_rect)
- else:
- x0, y0, w, h = self._rubberband_rect
- lw *= self.device_pixel_ratio
- dash *= self.device_pixel_ratio
+ x0, y0, w, h = (dim / self.device_pixel_ratio
+ for dim in self._rubberband_rect)
  x1 = x0 + w
  y1 = y0 + h
 

lib/matplotlib/backends/backend_gtk4cairo.py

@@ -5,7 +5,10 @@
 
 
 class FigureCanvasGTK4Cairo(FigureCanvasCairo, FigureCanvasGTK4):
- _context_is_scaled = True
+ def _set_device_pixel_ratio(self, ratio):
+ # Cairo in GTK4 always uses logical pixels, so we don't need to do anything for
+ # changes to the device pixel ratio.
+ return False
 
  def on_draw_event(self, widget, ctx):
  if self._idle_draw_id:
@@ -16,15 +19,11 @@ def on_draw_event(self, widget, ctx):
  with (self.toolbar._wait_cursor_for_draw_cm() if self.toolbar
  else nullcontext()):
  self._renderer.set_context(ctx)
- scale = self.device_pixel_ratio
- # Scale physical drawing to logical size.
- ctx.scale(1 / scale, 1 / scale)
  allocation = self.get_allocation()
  Gtk.render_background(
  self.get_style_context(), ctx,
  allocation.x, allocation.y,
  allocation.width, allocation.height)
- self._renderer.dpi = self.figure.dpi
  self.figure.draw(self._renderer)