/*
* Copyright (c) 2024 Huawei Device Co., Ltd.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { image } from '@kit.ImageKit';
import { matrix4, window } from '@kit.ArkUI';
import { OffsetModel } from '../model/OffsetModel';
import { ScaleModel } from '../model/ScaleModel';
import { runWithAnimation } from '../utils/FuncUtils';
import { windowSizeManager } from '../utils/Managers';
import { BusinessError } from '@kit.BasicServicesKit';
// TODO：知识点：组件复用
@Reusable
@Component
export struct ImageItemView {
@Consume private bgc: Color;
@Link isEnableSwipe: boolean; // TODO：需求：多图切换
@State isEnableOffset: boolean = false;
@State imageScaleInfo: ScaleModel = new ScaleModel(1.0, 1.0, 1.5, 0.3);
@State imageOffsetInfo: OffsetModel = new OffsetModel(0, 0);
@State matrix: matrix4.Matrix4Transit = matrix4.identity().copy();
@State imagePixelMap: image.PixelMap | null = null; // 当前图片pixelMap，用于Image组件显示
@State fitWH: "width" | "height" | undefined = undefined; // 表示当前图片是根据宽度适配还是高度适配
@State imageDefaultSize: image.Size = { width: 0, height: 0 }; // 图片默认大小，即，与屏幕大小最适配的显示大小
imageUri: string = ""; // 当前图片uri
imageWHRatio: number = 0; // 图片原始宽高比
aboutToAppear(): void {
this.initCurrentImageInfo();
}
/**
* 根据图片宽高比及窗口大小计算图片的默认宽高，即，图片最适配屏幕的大小
* @param imageWHRatio：图片原始宽高比
* @param size：窗口大小{with:number,height:number}
* @returns image.Size
*/
calcImageDefaultSize(imageWHRatio: number, size: window.Size): image.Size {
let width = 0
let height = 0;
if (imageWHRatio > size.width / size.height) {
// 图片宽高比大于屏幕宽高比，图片默认以屏幕宽度进行显示
width = size.width;
height = size.width / imageWHRatio;
} else {
height = size.height;
width = size.height * imageWHRatio;
}
return { width: width, height: height };
}
/**
* TODO：知识点：根据图片大小（宽高<=屏幕宽高）和屏幕大小计算图片放大适配屏幕进行显示的缩放倍率
* @param imageSize：图片当前大小
* @param windowSize：窗口大小
* @returns：缩放倍率
*/
calcFitScaleRatio(imageSize: image.Size, windowSize: window.Size): number {
let ratio: number = 1.0;
if (windowSize.width > imageSize.width) {
ratio = windowSize.width / imageSize.width;
} else {
ratio = windowSize.height / imageSize.height;
}
return ratio;
}
/**
* 设置当前图片的相关信息：uri、whRatio、pixelMap、fitWH、defaultSize、maxScaleValue
* TODO：知识点：提前获取图片的信息，以进行Image组件的尺寸设置及后续的相关计算
*/
initCurrentImageInfo(): void {
this.matrix = matrix4.identity().copy();
const imageSource: image.ImageSource = image.createImageSource(this.imageUri);
imageSource.getImageInfo(0).then((data: image.ImageInfo) => {
this.imageWHRatio = data.size.width / data.size.height;
this.imageDefaultSize = this.calcImageDefaultSize(this.imageWHRatio, windowSizeManager.get());
if (this.imageDefaultSize.width === windowSizeManager.get().width) {
this.fitWH = "width";
} else {
this.fitWH = "height";
}
this.imageScaleInfo.maxScaleValue += this.fitWH === "width" ?
(windowSizeManager.get().height / this.imageDefaultSize.height) :
(windowSizeManager.get().width / this.imageDefaultSize.width);
}).catch((err: BusinessError) => {
console.error(`[error][getImageInfo]${err.message}`);
});
imageSource.createPixelMap().then((data: image.PixelMap) => {
this.imagePixelMap = data;
}).catch((err: BusinessError) => {
console.error(`[error][createPixelMap]${err.message}`);
});
this.isEnableOffset = false;
this.imageScaleInfo.reset();
this.imageOffsetInfo.reset();
}
/**
* 在图片消失时，将当前图片的信息设置为默认值
*/
resetCurrentImageInfo(): void {
this.imageScaleInfo.reset();
this.imageOffsetInfo.reset();
this.matrix = matrix4.identity().copy();
}
/**
* TODO：需求：在偏移时评估是否到达边界，以便进行位移限制与图片的切换
* @returns：长度为4的boolean数组，表示上下左右是否到达边界
*/
evaluateBound(): boolean[] {
return [false, false, false, false];
}
build() {
Stack() {
Image(this.imagePixelMap)// TODO：知识点：宽高只根据其尺寸设置一个，通过保持宽高比来设置另一个属性
.width(this.fitWH === "width" ? $r("app.string.imageviewer_image_default_width") : undefined)
.height(this.fitWH === "height" ? $r("app.string.imageviewer_image_default_height") : undefined)
.aspectRatio(this.imageWHRatio)
.objectFit(ImageFit.Cover)// TODO：知识点：保持宽高比进行缩放，可以超出父组件，以便实现多图切换的增强功能
.autoResize(false)
.transform(this.matrix)// TODO：知识点：通过matrix控制图片的缩放
.defaultFocus(true)
.expandSafeArea([SafeAreaType.SYSTEM], [SafeAreaEdge.TOP, SafeAreaEdge.BOTTOM])
.offset({
// TODO：知识点：通过offset控制图片的偏移
x: this.imageOffsetInfo.currentX,
y: this.imageOffsetInfo.currentY
})
}
.onBlur(() => {
this.resetCurrentImageInfo();
})
.backgroundColor(this.bgc)
.alignContent(Alignment.Center)
.expandSafeArea([SafeAreaType.SYSTEM], [SafeAreaEdge.TOP, SafeAreaEdge.BOTTOM])
.width($r("app.string.imageviewer_image_item_stack_width"))
.height($r("app.string.imageviewer_image_item_stack_height"))
.gesture(
GestureGroup(
GestureMode.Exclusive,
// TODO：知识点：双击切换图片大小
TapGesture({ count: 2 })
.onAction(() => {
let fn: Function;
// 已经是放大状态下，双击缩小
if (this.imageScaleInfo.scaleValue > this.imageScaleInfo.defaultScaleValue) {
fn = () => {
this.isEnableSwipe = true;
this.imageScaleInfo.reset();
this.imageOffsetInfo.reset();
this.matrix = matrix4.identity().copy();
};
} else {
// 已经是缩小状态，双击放大
fn = () => {
this.isEnableSwipe = false;
const ratio: number = this.calcFitScaleRatio(this.imageDefaultSize, windowSizeManager.get());
this.imageScaleInfo.scaleValue = ratio;
this.imageOffsetInfo.reset();
this.matrix = matrix4.identity().scale({
x: ratio,
y: ratio,
}).copy();
this.imageScaleInfo.stash();
}
}
runWithAnimation(fn);
}),
// 单击切换背景色
TapGesture({ count: 1 }).onAction(() => {
runWithAnimation(() => {
this.bgc = this.bgc === Color.White ? Color.Black : Color.White;
});
}),
// TODO：知识点：双指捏合缩放图片
PinchGesture({ fingers: 2, distance: 1 })
.onActionUpdate((event: GestureEvent) => {
this.imageScaleInfo.scaleValue = this.imageScaleInfo.lastValue * event.scale;
// TODO：知识点：缩放时不允许大于最大缩放因子+额外缩放因子，不允许小于默认大小-额外缩放因子，额外缩放因子用于提升用户体验
if (this.imageScaleInfo.scaleValue > this.imageScaleInfo.maxScaleValue *
(1 + this.imageScaleInfo.extraScaleValue)
) {
this.imageScaleInfo.scaleValue = this.imageScaleInfo.maxScaleValue *
(1 + this.imageScaleInfo.extraScaleValue);
}
if (this.imageScaleInfo.scaleValue < this.imageScaleInfo.defaultScaleValue *
(1 - this.imageScaleInfo.extraScaleValue)) {
this.imageScaleInfo.scaleValue = this.imageScaleInfo.defaultScaleValue *
(1 - this.imageScaleInfo.extraScaleValue);
}
// TODO：知识点：matrix默认缩放中心为组件中心
this.matrix = matrix4.identity().scale({
x: this.imageScaleInfo.scaleValue,
y: this.imageScaleInfo.scaleValue,
}).copy();
console.debug(this.imageScaleInfo.toString());
})
.onActionEnd((event: GestureEvent) => {
/**
* TODO：知识点：当小于默认大小时，恢复为默认大小
*/
if (this.imageScaleInfo.scaleValue < this.imageScaleInfo.defaultScaleValue) {
runWithAnimation(() => {
this.imageScaleInfo.reset();
this.imageOffsetInfo.reset();
this.matrix = matrix4.identity().copy();
})
}
// TODO：知识点：当大于最大缩放因子时，恢复到最大
if (this.imageScaleInfo.scaleValue > this.imageScaleInfo.maxScaleValue) {
runWithAnimation(() => {
this.imageScaleInfo.scaleValue = this.imageScaleInfo.maxScaleValue;
this.matrix = matrix4.identity()
.scale({
x: this.imageScaleInfo.maxScaleValue,
y: this.imageScaleInfo.maxScaleValue
});
})
}
this.imageScaleInfo.stash();
}),
// TODO：知识点：滑动图片
PanGesture({ fingers: 1 })// TODO：需求：默认大小下左右滑动应当是切换图片
.onActionUpdate((event: GestureEvent) => {
if (this.imageScaleInfo.scaleValue === this.imageScaleInfo.defaultScaleValue) {
// 默认大小下不允许移动
return;
}
this.imageOffsetInfo.currentX = this.imageOffsetInfo.lastX + event.offsetX;
this.imageOffsetInfo.currentY = this.imageOffsetInfo.lastY + event.offsetY;
})
.onActionEnd((event: GestureEvent) => {
this.imageOffsetInfo.stash();
})
),
)
}
}