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449f4a6673
* Update project.pbxproj files to say Flutter rather than Chromium Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright. * Update the copyright notice checker to require a standard notice on all files * Update copyrights on Dart files. (This was a mechanical commit.) * Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine. Some were already marked "The Flutter Authors", not clear why. Their dates have been normalized. Some were missing the blank line after the license. Some were randomly different in trivial ways for no apparent reason (e.g. missing the trailing period). * Clean up the copyrights in non-Dart files. (Manual edits.) Also, make sure templates don't have copyrights. * Fix some more ORGANIZATIONNAMEs
93 lines
3.9 KiB
Dart
93 lines
3.9 KiB
Dart
// Copyright 2014 The Flutter 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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// This example shows how to draw some bi-directional text using the raw
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// interface to the engine.
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import 'dart:typed_data';
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import 'dart:ui' as ui;
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// A paragraph represents a rectangular region that contains some text.
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ui.Paragraph paragraph;
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ui.Picture paint(ui.Rect paintBounds) {
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final ui.PictureRecorder recorder = ui.PictureRecorder();
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final ui.Canvas canvas = ui.Canvas(recorder, paintBounds);
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final double devicePixelRatio = ui.window.devicePixelRatio;
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final ui.Size logicalSize = ui.window.physicalSize / devicePixelRatio;
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canvas.translate(logicalSize.width / 2.0, logicalSize.height / 2.0);
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canvas.drawRect(const ui.Rect.fromLTRB(-100.0, -100.0, 100.0, 100.0),
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ui.Paint()..color = const ui.Color.fromARGB(255, 0, 255, 0));
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// The paint method of Paragraph draws the contents of the paragraph onto the
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// given canvas.
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canvas.drawParagraph(paragraph, ui.Offset(-paragraph.width / 2.0, (paragraph.width / 2.0) - 125.0));
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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.window.devicePixelRatio;
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final Float64List deviceTransform = 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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final ui.SceneBuilder sceneBuilder = ui.SceneBuilder()
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..pushTransform(deviceTransform)
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..addPicture(ui.Offset.zero, picture)
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..pop();
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return sceneBuilder.build();
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}
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void beginFrame(Duration timeStamp) {
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final ui.Rect paintBounds = ui.Offset.zero & (ui.window.physicalSize / ui.window.devicePixelRatio);
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final ui.Picture picture = paint(paintBounds);
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final ui.Scene scene = composite(picture, paintBounds);
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ui.window.render(scene);
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}
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void main() {
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// To create a paragraph of text, we use ParagraphBuilder.
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final ui.ParagraphBuilder builder = ui.ParagraphBuilder(
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// The text below has a primary direction of left-to-right.
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// The embedded text has other directions.
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// If this was TextDirection.rtl, the "Hello, world" text would end up on
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// the other side of the right-to-left text.
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ui.ParagraphStyle(textDirection: ui.TextDirection.ltr),
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)
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// We first push a style that turns the text blue.
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..pushStyle(ui.TextStyle(color: const ui.Color(0xFF0000FF)))
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..addText('Hello, ')
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// The next run of text will be bold.
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..pushStyle(ui.TextStyle(fontWeight: ui.FontWeight.bold))
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..addText('world. ')
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// The pop() command signals the end of the bold styling.
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..pop()
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// We add text to the paragraph in logical order. The paragraph object
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// understands bi-directional text and will compute the visual ordering
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// during layout.
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..addText('هذا هو قليلا طويلة من النص الذي يجب التفاف .')
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// The second pop() removes the blue color.
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..pop()
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// We can add more text with the default styling.
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..addText(' و أكثر قليلا لجعله أطول. ')
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..addText('สวัสดี');
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// When we're done adding styles and text, we build the Paragraph object, at
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// which time we can apply styling that affects the entire paragraph, such as
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// left, right, or center alignment. Once built, the contents of the paragraph
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// cannot be altered, but sizing and positioning information can be updated.
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paragraph = builder.build()
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// Next, we supply a width that the text is permitted to occupy and we ask
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// the paragraph to the visual position of each its glyphs as well as its
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// overall size, subject to its sizing constraints.
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..layout(const ui.ParagraphConstraints(width: 180.0));
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// Finally, we register our beginFrame callback and kick off the first frame.
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ui.window.onBeginFrame = beginFrame;
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ui.window.scheduleFrame();
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}
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