View->Text Size->Increase (cmd+)

On my mbp, I increase the size of my font via the shortcut key (cmd+... applekey with plus key). How is this feature implemented?

1. search mxr for "Text Size"
Results:

/minimo/chrome/locale/en-US/minimo.dtd,

 * line 30 -- <!--ENTITY textSizePlus.label "Text Size +"-->
 * line 31 -- <!--ENTITY textSizeMinus.label "Text Size -"-->

2. search for textSizePlus.label

/minimo/chrome/content/minimo.xul,

  * line 329 -- label="&textSizePlus.label;"

3. open up the minimo.xul to see if I can find a function
Side Question: What is minimo? it looks important, like it defines the main menu for firefox browser.
Minimo is the windows mobile browser... DOH, Im sure Dave told us about that in class too

Ok Restart

1. search mxr for "Text Size"
Results:

/browser/locales/en-US/chrome/browser/browser.dtd,

  * line 292 -- <!--ENTITY textSize.label "Text Size"-->

2. search for textSize.label
Results:

/browser/base/content/browser-menubar.inc,

  * line 174 -- <menu id="viewTextZoomMenu" label="&textSize.label;" accesskey="&textSize.accesskey;" observes="isImage">
</menu>

3. open the source and look for a function
Results:

174                 <menu id="viewTextZoomMenu" label="&textSize.label;" accesskey="&textSize.accesskey;" observes="isImage">
175                   <menupopup>                  
176                     <menuitem key="key_textZoomEnlarge" label="&textZoomEnlargeCmd.label;" accesskey="&textZoomEnlargeCmd.accesskey;" 177="" command="cmd_textZoomEnlarge">
178                     <menuitem key="key_textZoomReduce" label="&textZoomReduceCmd.label;" accesskey="&textZoomReduceCmd.accesskey;" 179="" command="cmd_textZoomReduce">
180                     <menuseparator>
181                     <menuitem key="key_textZoomReset" label="&textZoomResetCmd.label;" accesskey="&textZoomResetCmd.accesskey;" 182="" command="cmd_textZoomReset">
183                   </menuitem>
184               
</menuseparator></menuitem></menuitem></menupopup>

4. command="cmd_textZoomEnlarge" ??? look for that
Results:

/browser/base/content/browser-sets.inc,

  * line 105 -- <command id="cmd_textZoomEnlarge" oncommand="TextZoom.enlarge()">
</command>

5. TextZoom looks like a class, lets do an Identifier Search

 73   __zoomManager: null,
74   get _zoomManager() {
75     if (!this.__zoomManager)
76       this.__zoomManager = ZoomManager.prototype.getInstance();
77     return this.__zoomManager;
78   },

236   enlarge: function TextZoom_enlarge() {
237     this._zoomManager.enlarge();
238     this._applySettingToPref();
239   },

So basically when a textZoomEnlargeCmd.label or a textZoomEnlargeCmd.accesskey occurs the TextZoom.enlarge function is ran... this in turn asks the ZoomManager to run things for it. What is the ZoomManager (obviously a singleton), What does it do?

6. Search for ZoomManager
Constructor

  49 function ZoomManager() {
 50   this.bundle = document.getElementById("bundle_viewZoom");
 51
 52   // factorAnchor starts on factorOther
 53   this.factorOther = parseInt(this.bundle.getString("valueOther"));
 54   this.factorAnchor = this.factorOther;
 55 }

enlarge method

 102   enlarge : function() {
103     this.jump(1);
104   },

jump method

 153   jump : function(aDirection) {
154     if (aDirection != -1 && aDirection != 1)
155       throw Components.results.NS_ERROR_INVALID_ARG;
156
157     this.ensureZoomFactors();
158
159     var currentZoom = this.textZoom;
160     var insertIndex = -1;
161     var stepFactor = parseFloat(this.bundle.getString("stepFactor"));
162
163     // temporarily add factorOther to list
164     if (this.isZoomInRange(this.factorOther)) {
165       insertIndex = 0;
166       while (this.zoomFactors[insertIndex] < this.factorOther)
167         ++insertIndex;
168
169       if (this.zoomFactors[insertIndex] != this.factorOther)
170         this.zoomFactors.splice(insertIndex, 0, this.factorOther);
171     }
172
173     var factor;
174     var done = false;
175
176     if (this.isZoomInRange(currentZoom)) {
177       var index = this.indexOf(currentZoom);
178       if (aDirection == -1 && index == 0 ||
179           aDirection ==  1 && index == this.zoomFactors.length - 1) {
180         this.steps = 0;
181         this.factorAnchor = this.zoomFactors[index];
182       } else {
183         factor = this.zoomFactors[index + aDirection];
184         done = true;
185       }
186     }
187
188     if (!done) {
189       this.steps += aDirection;
190       factor = this.factorAnchor * Math.pow(stepFactor, this.steps);
191       if (factor < this.MIN || factor > this.MAX) {
192         this.steps -= aDirection;
193         factor = this.factorAnchor * Math.pow(stepFactor, this.steps);
194       }
195       factor = Math.round(factor);
196       if (this.isZoomInRange(factor))
197         factor = this.snap(factor);
198       else
199         this.factorOther = factor;
200     }
201
202     if (insertIndex != -1)
203       this.zoomFactors.splice(insertIndex, 1);
204
205     this.textZoom = factor;
206   },

Well this is where the code is... ZoomManager.jump. The browser is defined in the browser-menubar.inc, which is an include file for the browser.xul . Browser.xul is the user interface definition for the firefox browser.