kmpdfkit_demo/lib/tools/common/widgets/cpdf_image_slider_thumb_shape.dart

import 'package:flutter/material.dart';

import 'package:flutter/services.dart';
import 'dart:ui' as ui;

///  Copyright © 2014-2023 PDF Technologies, Inc. All Rights Reserved.
///
///  THIS SOURCE CODE AND ANY ACCOMPANYING DOCUMENTATION ARE PROTECTED BY INTERNATIONAL COPYRIGHT LAW
///  AND MAY NOT BE RESOLD OR REDISTRIBUTED. USAGE IS BOUND TO THE ComPDFKit LICENSE AGREEMENT.
///  UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS SUBJECT TO CIVIL AND CRIMINAL PENALTIES.
///  This notice may not be removed from this file.

class CPDFImageSliderThumbShape extends SliderComponentShape {
  final double imageWidth;
  final double imageHeight;
  final ui.Image image;

  CPDFImageSliderThumbShape({
    this.imageWidth = 20,
    this.imageHeight = 20,
    required this.image,
  });

  @override
  Size getPreferredSize(bool isEnabled, bool isDiscrete) {
    return Size(imageWidth, imageHeight);
  }

  @override
  void paint(
    PaintingContext context,
    Offset center, {
    Animation<double>? activationAnimation,
    Animation<double>? enableAnimation,
    bool? isDiscrete,
    TextPainter? labelPainter,
    RenderBox? parentBox,
    SliderThemeData? sliderTheme,
    TextDirection? textDirection,
    double? value,
    double? textScaleFactor,
    Size? sizeWithOverflow,
  })  {
    final canvas = context.canvas;
    final imageOffset =
        Offset(center.dx - imageWidth / 2, center.dy - imageHeight / 2);

    // 计算缩放比例
    final double targetWidth = imageWidth; // 目标宽度
    final double targetHeight = imageHeight; // 目标高度
    final double scaleX = targetWidth / image.width.toDouble();
    final double scaleY = targetHeight / image.height.toDouble();
    final double scale = scaleX < scaleY ? scaleX : scaleY;

    // 计算缩放后的图片尺寸
    final double destWidth = image.width.toDouble() * scale;
    final double destHeight = image.height.toDouble() * scale;
    // canvas.translate(imageOffset.dx, imageOffset.dy);
    // canvas.rotate(1.6);

    // 绘制图片，并指定位置和大小
    final paint = Paint();
    final srcRect = Rect.fromLTWH(0, 0, image.width.toDouble(), image.height.toDouble());
    final dstRect = Rect.fromLTWH(imageOffset.dx, imageOffset.dy, destWidth, destHeight);

    canvas.drawImageRect(image, srcRect, dstRect, paint);
  }
}