| // Copyright 2015 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| import 'dart:ui' as ui; |
| import 'dart:typed_data'; |
| |
| void drawText(ui.Canvas canvas, String lh) { |
| ui.Paint paint = new ui.Paint(); |
| |
| // offset down |
| canvas.translate(0.0, 100.0); |
| |
| // set up the text |
| ui.Document document = new ui.Document(); |
| ui.Text arabic = document.createText("مرحبا"); |
| ui.Text english = document.createText(" Hello"); |
| ui.Element block = document.createElement('div'); |
| block.style['display'] = 'paragraph'; |
| block.style['font-family'] = 'monospace'; |
| block.style['font-size'] = '50px'; |
| block.style['line-height'] = lh; |
| block.style['color'] = '#0000A0'; |
| block.appendChild(arabic); |
| block.appendChild(english); |
| ui.LayoutRoot layoutRoot = new ui.LayoutRoot(); |
| layoutRoot.rootElement = block; |
| layoutRoot.maxWidth = ui.view.width - 20.0; // you need to set a width for this to paint |
| layoutRoot.layout(); |
| |
| // draw a line at the text's baseline |
| ui.Path path = new ui.Path(); |
| path.moveTo(0.0, 0.0); |
| path.lineTo(block.maxContentWidth, 0.0); |
| path.moveTo(0.0, block.alphabeticBaseline); |
| path.lineTo(block.maxContentWidth, block.alphabeticBaseline); |
| path.moveTo(0.0, block.height); |
| path.lineTo(block.maxContentWidth, block.height); |
| paint |
| ..color = const ui.Color(0xFFFF9000) |
| ..style = ui.PaintingStyle.stroke |
| ..strokeWidth = 3.0; |
| canvas.drawPath(path, paint); |
| |
| // paint the text |
| layoutRoot.paint(canvas); |
| } |
| |
| ui.Picture paint(ui.Rect paintBounds) { |
| ui.PictureRecorder recorder = new ui.PictureRecorder(); |
| ui.Canvas canvas = new ui.Canvas(recorder, paintBounds); |
| |
| ui.Paint paint = new ui.Paint() |
| ..color = const ui.Color(0xFFFFFFFF) |
| ..style = ui.PaintingStyle.fill; |
| canvas.drawRect(new ui.Rect.fromLTRB(0.0, 0.0, ui.view.width, ui.view.height), paint); |
| |
| canvas.translate(10.0, 0.0); |
| drawText(canvas, '1.0'); |
| drawText(canvas, 'lh'); |
| |
| return recorder.endRecording(); |
| } |
| |
| ui.Scene composite(ui.Picture picture, ui.Rect paintBounds) { |
| final double devicePixelRatio = ui.view.devicePixelRatio; |
| ui.Rect sceneBounds = new ui.Rect.fromLTWH(0.0, 0.0, ui.view.width * devicePixelRatio, ui.view.height * devicePixelRatio); |
| Float64List deviceTransform = new Float64List(16) |
| ..[0] = devicePixelRatio |
| ..[5] = devicePixelRatio |
| ..[10] = 1.0 |
| ..[15] = 1.0; |
| ui.SceneBuilder sceneBuilder = new ui.SceneBuilder(sceneBounds) |
| ..pushTransform(deviceTransform) |
| ..addPicture(ui.Offset.zero, picture, paintBounds) |
| ..pop(); |
| return sceneBuilder.build(); |
| } |
| |
| void beginFrame(double timeStamp) { |
| ui.Rect paintBounds = new ui.Rect.fromLTWH(0.0, 0.0, ui.view.width, ui.view.height); |
| ui.Picture picture = paint(paintBounds); |
| ui.Scene scene = composite(picture, paintBounds); |
| ui.view.scene = scene; |
| } |
| |
| void main() { |
| ui.view.setFrameCallback(beginFrame); |
| ui.view.scheduleFrame(); |
| } |