labelingqgis
I'd like to use callout/balloon labels for a vector layer in QGIS 2.0. The only way I can see to do this is to position an ordinary label where I want it and then draw an empty text annotation box behind the label.
I've tried using an HTML annotation but I can't work our how to link to a feature attribute using HTML.
I understand that I could use [% "attribute name" %] in the label (this results in a blank label), but how do I include the layer name in the html?
In QGIS 2.0, you can create background rectangles, ovals or custom SVG shapes without the need for a plugin. Just go to Layer Properties | Label | Background section.
If you want to code something. This might be a starting point: http://doc.qgis.org/api/qgspallabeling_8cpp_source.html#l04333
A solution came by digging deeper into the label style within the properties of the feature class. Before this, I was trying to use the drawing toolbar to place every callout label individually. The automatic placement of callout labels is achieved by...
1.)Right click the feature class and going to "Properties".
2.)Click the "Labels" tab.
3.)Click the "Symbol..." button.
4.)Click the "Edit Symbol..." button.
5.)Click the "Advanced Text" tab.
6.)Select the "Text Background" check box and hit "Properties".
Within this dialogue there are several options for producing callout labels. This, in combination with the MapPlex label engine make callout labels much more usable that I had originally thought when just using the "drawing toolbar". Here is a screen shot from the callout label dialogue.
Best Answer
Someone answered my question in a way that could help you using html annotations. QGIS html annotation relative paths under layer properties, display, you can insert the html to be displayed when hovering over features.