@@ -297,3 +297,115 @@ def test_webagg_toolbar_pan(random_port, page):
297297# Contracts in y-direction.
298298assert ax .viewLim .y1 == orig_lim .y1
299299assert ax .viewLim .y0 < orig_lim .y0 - orig_lim .height / 2
300+
301+
302+ @pytest .mark .backend ('webagg' )
303+ def test_webagg_toolbar_zoom (random_port ,page ):
304+ from playwright .sync_api import expect
305+
306+ fig ,ax = plt .subplots (facecolor = 'w' )
307+ ax .plot ([3 ,2 ,1 ])
308+ orig_lim = ax .viewLim .frozen ()
309+ # Make figure coords ~= axes coords, with ticks visible for inspection.
310+ ax .set_position ([0 ,0 ,1 ,1 ])
311+ ax .tick_params (axis = 'y' ,direction = 'in' ,pad = - 22 )
312+ ax .tick_params (axis = 'x' ,direction = 'in' ,pad = - 15 )
313+
314+ # Don't start the Tornado event loop, but use the existing event loop
315+ # started by the `page` fixture.
316+ WebAggApplication .initialize ()
317+ WebAggApplication .started = True
318+
319+ page .goto (f'http://{ WebAggApplication .address } { WebAggApplication .port } )
320+
321+ canvas = page .locator ('canvas.mpl-canvas' )
322+ expect (canvas ).to_be_visible ()
323+ home = page .locator ('button.mpl-widget' ).nth (0 )
324+ expect (home ).to_be_visible ()
325+ pan = page .locator ('button.mpl-widget' ).nth (3 )
326+ expect (pan ).to_be_visible ()
327+ zoom = page .locator ('button.mpl-widget' ).nth (4 )
328+ expect (zoom ).to_be_visible ()
329+
330+ active_re = re .compile (r'active' )
331+ expect (pan ).not_to_have_class (active_re )
332+ expect (zoom ).not_to_have_class (active_re )
333+ assert ax .get_navigate_mode ()is None
334+ zoom .click ()
335+ expect (pan ).not_to_have_class (active_re )
336+ expect (zoom ).to_have_class (active_re )
337+ assert ax .get_navigate_mode ()== 'ZOOM'
338+
339+ # Zoom 25% in on each side.
340+ bbox = canvas .bounding_box ()
341+ x ,y = bbox ['x' ]+ bbox ['width' ]/ 4 ,bbox ['y' ]+ bbox ['height' ]/ 4
342+ page .mouse .move (x ,y )
343+ page .mouse .down ()
344+ page .mouse .move (x + bbox ['width' ]/ 2 ,y + bbox ['height' ]/ 2 ,
345+ steps = 20 )
346+ page .mouse .up ()
347+
348+ assert ax .get_xlim ()== (orig_lim .x0 + orig_lim .width / 4 ,
349+ orig_lim .x1 - orig_lim .width / 4 )
350+ assert ax .get_ylim ()== (orig_lim .y0 + orig_lim .height / 4 ,
351+ orig_lim .y1 - orig_lim .height / 4 )
352+
353+ # Reset.
354+ home .click ()
355+
356+ # Zoom 25% in on each side, while holding 'x' key, to constrain the zoom
357+ # horizontally..
358+ bbox = canvas .bounding_box ()
359+ x ,y = bbox ['x' ]+ bbox ['width' ]/ 4 ,bbox ['y' ]+ bbox ['height' ]/ 4
360+ page .mouse .move (x ,y )
361+ page .mouse .down ()
362+ page .keyboard .down ('x' )
363+ page .mouse .move (x + bbox ['width' ]/ 2 ,y + bbox ['height' ]/ 2 ,
364+ steps = 20 )
365+ page .mouse .up ()
366+ page .keyboard .up ('x' )
367+
368+ assert ax .get_xlim ()== (orig_lim .x0 + orig_lim .width / 4 ,
369+ orig_lim .x1 - orig_lim .width / 4 )
370+ assert ax .get_ylim ()== (orig_lim .y0 ,orig_lim .y1 )
371+
372+ # Reset.
373+ home .click ()
374+
375+ # Zoom 25% in on each side, while holding 'y' key, to constrain the zoom
376+ # vertically.
377+ bbox = canvas .bounding_box ()
378+ x ,y = bbox ['x' ]+ bbox ['width' ]/ 4 ,bbox ['y' ]+ bbox ['height' ]/ 4
379+ page .mouse .move (x ,y )
380+ page .mouse .down ()
381+ page .keyboard .down ('y' )
382+ page .mouse .move (x + bbox ['width' ]/ 2 ,y + bbox ['height' ]/ 2 ,
383+ steps = 20 )
384+ page .mouse .up ()
385+ page .keyboard .up ('y' )
386+
387+ assert ax .get_xlim ()== (orig_lim .x0 ,orig_lim .x1 )
388+ assert ax .get_ylim ()== (orig_lim .y0 + orig_lim .height / 4 ,
389+ orig_lim .y1 - orig_lim .height / 4 )
390+
391+ # Reset.
392+ home .click ()
393+
394+ # Zoom 25% out on each side.
395+ bbox = canvas .bounding_box ()
396+ x ,y = bbox ['x' ]+ bbox ['width' ]/ 4 ,bbox ['y' ]+ bbox ['height' ]/ 4
397+ page .mouse .move (x ,y )
398+ page .mouse .down (button = 'right' )
399+ page .mouse .move (x + bbox ['width' ]/ 2 ,y + bbox ['height' ]/ 2 ,
400+ steps = 20 )
401+ page .mouse .up (button = 'right' )
402+
403+ # Limits were doubled, but based on the central point.
404+ cx = orig_lim .x0 + orig_lim .width / 2
405+ x0 = cx - orig_lim .width
406+ x1 = cx + orig_lim .width
407+ assert ax .get_xlim ()== (x0 ,x1 )
408+ cy = orig_lim .y0 + orig_lim .height / 2
409+ y0 = cy - orig_lim .height
410+ y1 = cy + orig_lim .height
411+ assert ax .get_ylim ()== (y0 ,y1 )