Merge pull request #2781 from Hixie/more-docs

Add yet more dartdocs.

packages/flutter/doc/styles.html

@@ -29,3 +29,21 @@
     font-size: 14px;
   }
 </style>
+
+<!-- The following rules are from http://google.github.io/material-design-icons/ -->
+<link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
+<style>
+  /* Rules for sizing the icon. */
+  .material-icons.md-18 { font-size: 18px; }
+  .material-icons.md-24 { font-size: 24px; }
+  .material-icons.md-36 { font-size: 36px; }
+  .material-icons.md-48 { font-size: 48px; }
+
+  /* Rules for using icons as black on a light background. */
+  .material-icons.md-dark { color: rgba(0, 0, 0, 0.54); }
+  .material-icons.md-dark.md-inactive { color: rgba(0, 0, 0, 0.26); }
+
+  /* Rules for using icons as white on a dark background. */
+  .material-icons.md-light { color: rgba(255, 255, 255, 1); }
+  .material-icons.md-light.md-inactive { color: rgba(255, 255, 255, 0.3); }
+</style>

packages/flutter/lib/src/painting/text_painter.dart

@@ -221,6 +221,22 @@ class TextSpan {
 }
 
 /// An object that paints a [TextSpan] tree into a [Canvas].
+///
+/// To use a [TextPainter], follow these steps:
+///
+/// 1. Create a [TextSpan] tree and pass it to the [TextPainter]
+///    constructor.
+///
+/// 2. Set the [maxWidth] property of the [TextPainter] to the width
+///    of the area into which the text should be painted.
+///
+/// 3. Call [layout] to prepare the paragraph.
+///
+/// 4. Call [paint] as often as desired to paint the paragraph.
+///
+/// If the width of the area into which the text is being painted
+/// changes, return to step 2. If the text to be painted changes,
+/// return to step 1.
 class TextPainter {
   TextPainter([ TextSpan text ]) {
     this.text = text;