michael@0: /* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: // The possible values of the "align" component of preserveAspectRatio.
michael@0: const ALIGN_VALS = ["none",
michael@0:                     "xMinYMin", "xMinYMid", "xMinYMax",
michael@0:                     "xMidYMin", "xMidYMid", "xMidYMax",
michael@0:                     "xMaxYMin", "xMaxYMid", "xMaxYMax"];
michael@0: 
michael@0: // The possible values of the "meetOrSlice" component of preserveAspectRatio.
michael@0: const MEETORSLICE_VALS = [ "meet", "slice" ];
michael@0: 
michael@0: const SVGNS   = "http://www.w3.org/2000/svg";
michael@0: const XLINKNS = "http://www.w3.org/1999/xlink";
michael@0: 
michael@0: // This is the separation between the x & y values of each <image> in a
michael@0: // generated grid.
michael@0: const IMAGE_OFFSET = 50;
michael@0: 
michael@0: function generateBorderRect(aX, aY, aWidth, aHeight) {
michael@0:   var rect = document.createElementNS(SVGNS, "rect");
michael@0:   rect.setAttribute("x", aX);
michael@0:   rect.setAttribute("y", aY);
michael@0:   rect.setAttribute("width", aWidth);
michael@0:   rect.setAttribute("height", aHeight);
michael@0:   rect.setAttribute("fill", "none");
michael@0:   rect.setAttribute("stroke", "black");
michael@0:   rect.setAttribute("stroke-width", "2");
michael@0:   rect.setAttribute("stroke-dasharray", "3 2");
michael@0:   return rect;
michael@0: }
michael@0: 
michael@0: // Returns an SVG <image> element with the given xlink:href, width, height,
michael@0: // and preserveAspectRatio=[aAlign aMeetOrSlice] attributes
michael@0: function generateImageElementForParams(aX, aY, aWidth, aHeight,
michael@0:                                        aHref, aAlign, aMeetOrSlice) {
michael@0:   var image = document.createElementNS(SVGNS, "image");
michael@0:   image.setAttribute("x", aX);
michael@0:   image.setAttribute("y", aY);
michael@0:   image.setAttribute("width", aWidth);
michael@0:   image.setAttribute("height", aHeight);
michael@0:   image.setAttributeNS(XLINKNS, "href", aHref);
michael@0:   image.setAttribute("preserveAspectRatio", aAlign + " " + aMeetOrSlice);
michael@0:   return image;
michael@0: }
michael@0: 
michael@0: // Returns a <g> element filled with a grid of <image> elements which each
michael@0: // have the specified aWidth & aHeight and which use all possible values of
michael@0: // preserveAspectRatio.
michael@0: //
michael@0: // The final "aBonusPARVal" argument (if specified) is used as the
michael@0: // preserveAspectRatio value on a bonus <image> element, added at the end.
michael@0: function generateImageGrid(aHref, aWidth, aHeight, aBonusPARVal) {
michael@0:   var grid = document.createElementNS(SVGNS, "g");
michael@0:   var y = 0;
michael@0:   var x = 0;
michael@0:   for (var i = 0; i < ALIGN_VALS.length; i++) {
michael@0:     // Jump to next line of grid, for every other "i" value.
michael@0:     // (every fourth entry)
michael@0:     if (i && i % 2 == 0) {
michael@0:       y += IMAGE_OFFSET;
michael@0:       x = 0;
michael@0:     }
michael@0:     var alignVal = ALIGN_VALS[i];
michael@0:     for (var j = 0; j < MEETORSLICE_VALS.length; j++) {
michael@0:       var meetorsliceVal = MEETORSLICE_VALS[j];
michael@0:       var border = generateBorderRect(x, y, aWidth, aHeight);
michael@0:       var image  = generateImageElementForParams(x, y, aWidth, aHeight,
michael@0:                                                  aHref, alignVal,
michael@0:                                                  meetorsliceVal);
michael@0:       grid.appendChild(border);
michael@0:       grid.appendChild(image);
michael@0:       x += IMAGE_OFFSET;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (aBonusPARVal) {
michael@0:     // Add one final entry with "bonus" pAR value.
michael@0:     y += IMAGE_OFFSET;
michael@0:     x = 0;
michael@0:     var border = generateBorderRect(x, y, aWidth, aHeight);
michael@0:     var image  = generateImageElementForParams(x, y, aWidth, aHeight,
michael@0:                                                aHref, aBonusPARVal, "");
michael@0:     grid.appendChild(border);
michael@0:     grid.appendChild(image);
michael@0:   }
michael@0: 
michael@0:   return grid;
michael@0: }
michael@0: 
michael@0: // Returns an SVG <symbol> element that...
michael@0: //  (a) has the given ID
michael@0: //  (b) contains only a <use> element to the given URI
michael@0: //  (c) has a hardcoded viewBox="0 0 10 10" attribute
michael@0: //  (d) has the given preserveAspectRatio=[aAlign aMeetOrSlice] attribute
michael@0: function generateSymbolElementForParams(aSymbolID, aHref,
michael@0:                                         aAlign, aMeetOrSlice) {
michael@0:   var use = document.createElementNS(SVGNS, "use");
michael@0:   use.setAttributeNS(XLINKNS, "href", aHref);
michael@0: 
michael@0:   var symbol = document.createElementNS(SVGNS, "symbol");
michael@0:   symbol.setAttribute("id", aSymbolID);
michael@0:   symbol.setAttribute("viewBox", "0 0 10 10");
michael@0:   symbol.setAttribute("preserveAspectRatio", aAlign + " " + aMeetOrSlice);
michael@0: 
michael@0:   symbol.appendChild(use);
michael@0:   return symbol;
michael@0: }
michael@0: 
michael@0: function generateUseElementForParams(aTargetURI, aX, aY, aWidth, aHeight) {
michael@0:   var use = document.createElementNS(SVGNS, "use");
michael@0:   use.setAttributeNS(XLINKNS, "href", aTargetURI);
michael@0:   use.setAttribute("x", aX);
michael@0:   use.setAttribute("y", aY);
michael@0:   use.setAttribute("width", aWidth);
michael@0:   use.setAttribute("height", aHeight);
michael@0:   return use;
michael@0: }
michael@0: 
michael@0: // Returns a <g> element filled with a grid of <use> elements which each
michael@0: // have the specified aWidth & aHeight and which reference <symbol> elements
michael@0: // with all possible values of preserveAspectRatio.  Each <symbol> contains
michael@0: // a <use> that links to the given URI, aHref.
michael@0: //
michael@0: // The final "aBonusPARVal" argument (if specified) is used as the
michael@0: // preserveAspectRatio value on a bonus <symbol> element, added at the end.
michael@0: function generateSymbolGrid(aHref, aWidth, aHeight, aBonusPARVal) {
michael@0:   var grid = document.createElementNS(SVGNS, "g");
michael@0:   var y = 0;
michael@0:   var x = 0;
michael@0:   for (var i = 0; i < ALIGN_VALS.length; i++) {
michael@0:     // Jump to next line of grid, for every other "i" value.
michael@0:     // (every fourth entry)
michael@0:     if (i && i % 2 == 0) {
michael@0:       y += IMAGE_OFFSET;
michael@0:       x = 0;
michael@0:     }
michael@0:     var alignVal = ALIGN_VALS[i];
michael@0:     for (var j = 0; j < MEETORSLICE_VALS.length; j++) {
michael@0:       var meetorsliceVal = MEETORSLICE_VALS[j];
michael@0:       var border = generateBorderRect(x, y, aWidth, aHeight);
michael@0: 
michael@0:       var symbolID = "symbol_" + alignVal + "_" + meetorsliceVal;
michael@0:       var symbol = generateSymbolElementForParams(symbolID, aHref,
michael@0:                                                   alignVal, meetorsliceVal);
michael@0:       var use = generateUseElementForParams("#" + symbolID,
michael@0:                                             x, y, aWidth, aHeight);
michael@0:       grid.appendChild(symbol); // This isn't painted
michael@0:       grid.appendChild(border);
michael@0:       grid.appendChild(use);
michael@0:       x += IMAGE_OFFSET;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (aBonusPARVal) {
michael@0:     // Add one final entry with "bonus" pAR value.
michael@0:     y += IMAGE_OFFSET;
michael@0:     x = 0;
michael@0:     var border = generateBorderRect(x, y, aWidth, aHeight);
michael@0:     var symbolID = "symbol_Bonus";
michael@0:     var symbol = generateSymbolElementForParams(symbolID, aHref,
michael@0:                                                 aBonusPARVal, "");
michael@0:     var use = generateUseElementForParams("#" + symbolID,
michael@0:                                           x, y, aWidth, aHeight);
michael@0:     grid.appendChild(symbol); // This isn't painted
michael@0:     grid.appendChild(border);
michael@0:     grid.appendChild(use);
michael@0:   }
michael@0: 
michael@0:   return grid;
michael@0: }