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SVG Tooltip#
This example shows how to create a tooltip that will show up whenhovering over a matplotlib patch.
Although it is possible to create the tooltip from CSS or javascript,here we create it in matplotlib and simply toggle its visibility onwhen hovering over the patch. This approach provides total control overthe tooltip placement and appearance, at the expense of more code upfront.
The alternative approach would be to put the tooltip content intitleattributes of SVG objects. Then, using an existing js/CSS library, itwould be relatively straightforward to create the tooltip in thebrowser. The content would be dictated by thetitle attribute, andthe appearance by the CSS.
- author:
David Huard
fromioimportBytesIOimportxml.etree.ElementTreeasETimportmatplotlib.pyplotaspltET.register_namespace("","http://www.w3.org/2000/svg")fig,ax=plt.subplots()# Create patches to which tooltips will be assigned.rect1=plt.Rectangle((10,-20),10,5,fc='blue')rect2=plt.Rectangle((-20,15),10,5,fc='green')shapes=[rect1,rect2]labels=['This is a blue rectangle.','This is a green rectangle']fori,(item,label)inenumerate(zip(shapes,labels)):patch=ax.add_patch(item)annotate=ax.annotate(labels[i],xy=item.get_xy(),xytext=(0,0),textcoords='offset points',color='w',ha='center',fontsize=8,bbox=dict(boxstyle='round, pad=.5',fc=(.1,.1,.1,.92),ec=(1.,1.,1.),lw=1,zorder=1))ax.add_patch(patch)patch.set_gid(f'mypatch_{i:03d}')annotate.set_gid(f'mytooltip_{i:03d}')# Save the figure in a fake file objectax.set_xlim(-30,30)ax.set_ylim(-30,30)ax.set_aspect('equal')f=BytesIO()plt.savefig(f,format="svg")# --- Add interactivity ---# Create XML tree from the SVG file.tree,xmlid=ET.XMLID(f.getvalue())tree.set('onload','init(event)')foriinshapes:# Get the index of the shapeindex=shapes.index(i)# Hide the tooltipstooltip=xmlid[f'mytooltip_{index:03d}']tooltip.set('visibility','hidden')# Assign onmouseover and onmouseout callbacks to patches.mypatch=xmlid[f'mypatch_{index:03d}']mypatch.set('onmouseover',"ShowTooltip(this)")mypatch.set('onmouseout',"HideTooltip(this)")# This is the script defining the ShowTooltip and HideTooltip functions.script=""" <script type="text/ecmascript"> <![CDATA[ function init(event) { if ( window.svgDocument == null ) { svgDocument = event.target.ownerDocument; } } function ShowTooltip(obj) { var cur = obj.id.split("_")[1]; var tip = svgDocument.getElementById('mytooltip_' + cur); tip.setAttribute('visibility', "visible") } function HideTooltip(obj) { var cur = obj.id.split("_")[1]; var tip = svgDocument.getElementById('mytooltip_' + cur); tip.setAttribute('visibility', "hidden") } ]]> </script> """# Insert the script at the top of the file and save it.tree.insert(0,ET.XML(script))ET.ElementTree(tree).write('svg_tooltip.svg')