Add a subfilter parameter to image-picker macro (#2391)

* Documentation and examples
* Fix the tag of image- and colour-picker macros in documentation

core/wiki/macros/image-picker.tid

@@ -11,10 +11,10 @@ $actions$
 </$button>
 \end
 
-\define image-picker(actions)
+\define image-picker(actions,subfilter:"")
 <div class="tc-image-chooser">
 
-<$list filter="[all[shadows+tiddlers]is[image]!has[draft.of]] -[type[application/pdf]] +[sort[title]]" variable="imageTitle">
+<$list filter="[all[shadows+tiddlers]is[image]$subfilter$!has[draft.of]] -[type[application/pdf]] +[sort[title]]" variable="imageTitle">
 
 <$macrocall $name="image-picker-inner" actions="""$actions$"""/>
 

editions/tw5.com/tiddlers/macros/examples/colour-picker_Macro_(Examples).tid

@@ -1,6 +1,6 @@
 created: 20160418152735536
 modified: 20160418155324847
-tags: [[changecount Macro]] [[Macro Examples]]
+tags: [[colour-picker Macro]] [[Macro Examples]]
 title: colour-picker Macro (Examples)
 type: text/vnd.tiddlywiki
 

editions/tw5.com/tiddlers/macros/examples/image-picker_Macro_(Example_2).tid

@@ -0,0 +1,17 @@
+created: 20160418155523369
+modified: 20160418155913663
+tags: 
+title: image-picker Macro (Example 2)
+type: text/vnd.tiddlywiki
+
+Image: <$edit-text tiddler='$:/_MyImage' tag='input' placeholder='(unset)' default=''/>
+
+<$transclude tiddler={{$:/_MyImage}}/>
+
+---
+
+<$macrocall $name='image-picker' actions="
+
+<$action-setfield $tiddler='$:/_MyImage' $value=<<imageTitle>>/>
+
+" subfilter="prefix[Language]"/>

editions/tw5.com/tiddlers/macros/examples/image-picker_Macro_(Examples).tid

@@ -1,7 +1,11 @@
 created: 20160418155539132
 modified: 20160418155621890
-tags: [[changecount Macro]] [[Macro Examples]]
+tags: [[image-picker Macro]] [[Macro Examples]]
 title: image-picker Macro (Examples)
 type: text/vnd.tiddlywiki
 
 <$macrocall $name=".example" n="1" eg={{image-picker Macro (Example 1)}}/>
+
+This next example shows how the <<.param subfilter>> parameter limits the list of images (here to those with the "Language" prefix):
+
+<$macrocall $name=".example" n="2" eg="{{image-picker Macro (Example 2)}}/>

editions/tw5.com/tiddlers/macros/image-picker_Macro.tid

@@ -1,4 +1,4 @@
-caption: colour-picker
+caption: image-picker
 created: 20160418155531395
 modified: 20160418155805435
 tags: Macros [[Core Macros]]
@@ -11,5 +11,11 @@ The <<.def image-picker>> [[macro|Macros]] displays an interactive image picker,
 
 ;actions
 : Wikitext for the action widgets that should be executed when the user selects an image. Within the text, the variable `imageTitle` contains the title of the tiddler containing the selected image.
+;subfilter
+: An optional extra [[filter step|Filter Step]], e.g. `tag[MyTag]`
+
+The images are selected by means of a [[filter expression|Filter Expression]], into which the <<.param subfilter>> parameter is spliced as follows:
+
+> `[all[shadows+tiddlers]is[image]$subfilter$!has[draft.of]] -[type[application/pdf]] +[sort[title]]`
 
 <<.macro-examples "image-picker">>