mirror of
https://github.com/flutter/flutter.git
synced 2025-06-03 00:51:18 +00:00
5491c8c146
This auto-formats all *.dart files in the repository outside of the `engine` subdirectory and enforces that these files stay formatted with a presubmit check. **Reviewers:** Please carefully review all the commits except for the one titled "formatted". The "formatted" commit was auto-generated by running `dev/tools/format.sh -a -f`. The other commits were hand-crafted to prepare the repo for the formatting change. I recommend reviewing the commits one-by-one via the "Commits" tab and avoiding Github's "Files changed" tab as it will likely slow down your browser because of the size of this PR. --------- Co-authored-by: Kate Lovett <katelovett@google.com> Co-authored-by: LongCatIsLooong <31859944+LongCatIsLooong@users.noreply.github.com>
61 lines
2.4 KiB
Dart
61 lines
2.4 KiB
Dart
// Copyright 2014 The Flutter Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
// This example shows how to show the text 'Hello, world.' using the raw
|
|
// interface to the engine.
|
|
|
|
import 'dart:ui' as ui;
|
|
|
|
// The FlutterView into which this example will draw; set in the main method.
|
|
late final ui.FlutterView view;
|
|
|
|
void beginFrame(Duration timeStamp) {
|
|
final double devicePixelRatio = view.devicePixelRatio;
|
|
final ui.Size logicalSize = view.physicalSize / devicePixelRatio;
|
|
|
|
final ui.ParagraphBuilder paragraphBuilder = ui.ParagraphBuilder(
|
|
ui.ParagraphStyle(textDirection: ui.TextDirection.ltr),
|
|
)..addText('Hello, world.');
|
|
final ui.Paragraph paragraph =
|
|
paragraphBuilder.build()..layout(ui.ParagraphConstraints(width: logicalSize.width));
|
|
|
|
final ui.Rect physicalBounds = ui.Offset.zero & (logicalSize * devicePixelRatio);
|
|
final ui.PictureRecorder recorder = ui.PictureRecorder();
|
|
final ui.Canvas canvas = ui.Canvas(recorder, physicalBounds);
|
|
canvas.scale(devicePixelRatio, devicePixelRatio);
|
|
canvas.drawParagraph(
|
|
paragraph,
|
|
ui.Offset(
|
|
(logicalSize.width - paragraph.maxIntrinsicWidth) / 2.0,
|
|
(logicalSize.height - paragraph.height) / 2.0,
|
|
),
|
|
);
|
|
final ui.Picture picture = recorder.endRecording();
|
|
|
|
final ui.SceneBuilder sceneBuilder =
|
|
ui.SceneBuilder()
|
|
// TODO(abarth): We should be able to add a picture without pushing a
|
|
// container layer first.
|
|
..pushClipRect(physicalBounds)
|
|
..addPicture(ui.Offset.zero, picture)
|
|
..pop();
|
|
|
|
view.render(sceneBuilder.build());
|
|
}
|
|
|
|
// This function is the primary entry point to your application. The engine
|
|
// calls main() as soon as it has loaded your code.
|
|
void main() {
|
|
// TODO(goderbauer): Create a window if embedder doesn't provide an implicit view to draw into.
|
|
assert(ui.PlatformDispatcher.instance.implicitView != null);
|
|
view = ui.PlatformDispatcher.instance.implicitView!;
|
|
|
|
// The engine calls onBeginFrame whenever it wants us to produce a frame.
|
|
ui.PlatformDispatcher.instance.onBeginFrame = beginFrame;
|
|
// Here we kick off the whole process by asking the engine to schedule a new
|
|
// frame. The engine will eventually call onBeginFrame when it is time for us
|
|
// to actually produce the frame.
|
|
ui.PlatformDispatcher.instance.scheduleFrame();
|
|
}
|