MathJax SVG AuthorInit / StartupHook rendering bug

[danielweck]

See discussion:
https://groups.google.com/d/msg/readium-dev/lGWYDvSMwdY/Vqm9OQk0PjIJ

The proposed fix is to remove the "AuthorInit" section:
https://raw.githubusercontent.com/readium/readium-js-viewer/develop/lib/mathjax/MathJax.js

AuthorInit: function () { 
        MathJax.Hub.Register.StartupHook("SVG Jax Ready", function () { 
            var SVG = MathJax.OutputJax.SVG, GLYPH = SVG.BBOX.GLYPH; 
            GLYPH.Augment({ 
                Init: function (scale, id, h, d, w, l, r, p) { 
                    var t = SVG.config.blacker, 
                        def = {"stroke-width": t}; 
                    if (p !== "") { 
                        def.d = "M" + p + "Z" 
                    } 
                    if (scale !== 1) { 
                        def.transform = "scale(" + scale + ")" 
                    } 
                    this.SUPER(arguments).Init.call(this, def); 
                    this.h = (h + t) * scale; 
                    this.d = (d + t) * scale; 
                    this.w = (w + t / 2) * scale; 
                    this.l = (l + t / 2) * scale; 
                    this.r = (r + t / 2) * scale; 
                    this.H = Math.max(0, this.h); 
                    this.D = Math.max(0, this.d); 
                    this.x = this.y = 0; 
                    this.scale = scale; 
                } 
            }); 
        }); 
    } 

Before proposed fix:

After (seems to work fine):

To test, edit

readium-js-viewer/epub_content/linear-algebra/EPUB/xhtml/titlepage.html

and add:

        <div class="foreign mathml">
           <math xmlns="http://www.w3.org/1998/Math/MathML">
              <mstyle displaystyle="true">
                 <mrow>
                    <mrow>
                       <mo>{</mo>
                       <mtable>
                          <mtr>
                             <mtd columnalign="left">
                                <mrow>
                                   <msub>
                                      <mrow>
                                         <mi>t</mi>
                                      </mrow>
                                      <mrow>
                                         <msub>
                                            <mrow>
                                               <mi>S</mi>
                                            </mrow>
                                            <mrow>
                                               <mi>i</mi>
                                            </mrow>
                                         </msub>
                                      </mrow>
                                   </msub>
                                   <mo>=</mo>
                                   <msub>
                                      <mrow>
                                         <mi>t</mi>
                                      </mrow>
                                      <mrow>
                                         <msub>
                                            <mrow>
                                               <mi>th</mi>
                                            </mrow>
                                            <mrow>
                                               <mi>i</mi>
                                            </mrow>
                                         </msub>
                                      </mrow>
                                   </msub>
                                </mrow>
                             </mtd>
                          </mtr>
                          <mtr>
                             <mtd columnalign="left">
                                <mrow>
                                   <msub>
                                      <mrow>
                                         <mi>t</mi>
                                      </mrow>
                                      <mrow>
                                         <msub>
                                            <mrow>
                                               <mi>E</mi>
                                            </mrow>
                                            <mrow>
                                               <mi>i</mi>
                                            </mrow>
                                         </msub>
                                      </mrow>
                                   </msub>
                                   <mo>=</mo>
                                   <msub>
                                      <mrow>
                                         <mi>t</mi>
                                      </mrow>
                                      <mrow>
                                         <msub>
                                            <mrow>
                                               <mi>th</mi>
                                            </mrow>
                                            <mrow>
                                               <mi>i</mi>
                                               <mo>+</mo>
                                               <mn>1</mn>
                                            </mrow>
                                         </msub>
                                      </mrow>
                                   </msub>
                                </mrow>
                             </mtd>
                          </mtr>
                       </mtable>
                       <mo> </mo>
                    </mrow>
                 </mrow>
              </mstyle>
           </math>
        </div>

[danielweck]

Follow up: I suggest we do not wait until the grunt build script is ready (see #216 ), and that we remove the AuthorInit section manually (must mirror in native apps too, iOS and OSX in particular as they now have a dedicated branch / Pull Request for MathJax injection).

[pkra]

Just for the record, the custom hack was leftover from @dpvc's contribution to the very first Readium Chrome Extension; back then it was a hack around an old Chrome issue.

This time around, it was not added by the MathJax single file build but during the integration by Readium devs, trying to keep the old configuration around.

[danielweck]

Thanks for the clarification, @pkra !

[danielweck]

Fixed (see references above, in readium-js-viewer as well as OSX / iOS native app launchers)