WIP - add extractor, generate snippet_data

node_modules/probe-image-size/lib/parse_sync/svg.js

@@ -0,0 +1,131 @@
+'use strict';
+
+/* eslint-disable consistent-return */
+
+function isWhiteSpace(chr) {
+  return chr === 0x20 || chr === 0x09 || chr === 0x0D || chr === 0x0A;
+}
+
+// Filter NaN, Infinity, < 0
+function isFinitePositive(val) {
+  return typeof val === 'number' && isFinite(val) && val > 0;
+}
+
+function canBeSvg(buf) {
+  var i = 0, max = buf.length;
+
+  while (i < max && isWhiteSpace(buf[i])) i++;
+
+  if (i === max) return false;
+  return buf[i] === 0x3c; /* < */
+}
+
+
+var SVG_HEADER_RE  = /<svg\s[^>]+>/;
+var SVG_WIDTH_RE   = /[^-]\bwidth="([^%]+?)"|[^-]\bwidth='([^%]+?)'/;
+var SVG_HEIGHT_RE  = /\bheight="([^%]+?)"|\bheight='([^%]+?)'/;
+var SVG_VIEWBOX_RE = /\bview[bB]ox="(.+?)"|\bview[bB]ox='(.+?)'/;
+var SVG_UNITS_RE   = /in$|mm$|cm$|pt$|pc$|px$|em$|ex$/;
+
+function svgAttrs(str) {
+  var width   = str.match(SVG_WIDTH_RE);
+  var height  = str.match(SVG_HEIGHT_RE);
+  var viewbox = str.match(SVG_VIEWBOX_RE);
+
+  return {
+    width:   width && (width[1] || width[2]),
+    height:  height && (height[1] || height[2]),
+    viewbox: viewbox && (viewbox[1] || viewbox[2])
+  };
+}
+
+
+function units(str) {
+  if (!SVG_UNITS_RE.test(str)) return 'px';
+
+  return str.match(SVG_UNITS_RE)[0];
+}
+
+
+module.exports = function (data) {
+  if (!canBeSvg(data)) return;
+
+  var str = '';
+
+  for (var i = 0; i < data.length; i++) {
+    // 1. We can't rely on buffer features
+    // 2. Don't care about UTF16 because ascii is enougth for our goals
+    str += String.fromCharCode(data[i]);
+  }
+
+  if (!SVG_HEADER_RE.test(str)) return;
+
+  var attrs  = svgAttrs(str.match(SVG_HEADER_RE)[0]);
+  var width  = parseFloat(attrs.width);
+  var height = parseFloat(attrs.height);
+
+  // Extract from direct values
+
+  if (attrs.width && attrs.height) {
+    if (!isFinitePositive(width) || !isFinitePositive(height)) return;
+
+    return {
+      width:  width,
+      height: height,
+      type:   'svg',
+      mime:   'image/svg+xml',
+      wUnits: units(attrs.width),
+      hUnits: units(attrs.height)
+    };
+  }
+
+  // Extract from viewbox
+
+  var parts = (attrs.viewbox || '').split(' ');
+  var viewbox = {
+    width:  parts[2],
+    height: parts[3]
+  };
+  var vbWidth  = parseFloat(viewbox.width);
+  var vbHeight = parseFloat(viewbox.height);
+
+  if (!isFinitePositive(vbWidth) || !isFinitePositive(vbHeight)) return;
+  if (units(viewbox.width) !== units(viewbox.height)) return;
+
+  var ratio = vbWidth / vbHeight;
+
+  if (attrs.width) {
+    if (!isFinitePositive(width)) return;
+
+    return {
+      width:  width,
+      height: width / ratio,
+      type:   'svg',
+      mime:   'image/svg+xml',
+      wUnits: units(attrs.width),
+      hUnits: units(attrs.width)
+    };
+  }
+
+  if (attrs.height) {
+    if (!isFinitePositive(height)) return;
+
+    return {
+      width:  height * ratio,
+      height: height,
+      type:   'svg',
+      mime:   'image/svg+xml',
+      wUnits: units(attrs.height),
+      hUnits: units(attrs.height)
+    };
+  }
+
+  return {
+    width:  vbWidth,
+    height: vbHeight,
+    type:   'svg',
+    mime:   'image/svg+xml',
+    wUnits: units(viewbox.width),
+    hUnits: units(viewbox.height)
+  };
+};