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