【图片旋转】HarmonyOS Codelab挑战赛记录
# 图片旋转## 项目启动
## 布局文件
在resource/base/layout 目录下修改 ability_main.xml
```xml
<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
xmlns:ohos="http://schemas.huawei.com/res/ohos"
ohos:height="match_parent"
ohos:width="match_parent"
ohos:orientation="vertical">
<Text
ohos:height="match_content"
ohos:width="match_content"
ohos:layout_alignment="horizontal_center"
ohos:text="HarmonyOS图像开发"
ohos:text_size="80"
ohos:top_margin="40vp"
/>
<DirectionalLayout
xmlns:ohos="http://schemas.huawei.com/res/ohos"
ohos:height="match_content"
ohos:width="match_content"
ohos:layout_alignment="horizontal_center"
ohos:orientation="horizontal"
ohos:top_margin="20vp">
<Button
ohos:id="$+id:whirl_image"
ohos:height="match_content"
ohos:width="match_content"
ohos:background_element="$graphic:background_button"
ohos:padding="12vp"
ohos:right_margin="5vp"
ohos:text="旋转"
ohos:text_size="20vp"
ohos:top_margin="10vp">
</Button>
<Button
ohos:id="$+id:crop_image"
ohos:height="match_content"
ohos:width="match_content"
ohos:background_element="$graphic:background_button"
ohos:left_margin="5vp"
ohos:padding="12vp"
ohos:text="剪裁"
ohos:text_size="20vp"
ohos:top_margin="10vp">
</Button>
<Button
ohos:id="$+id:scale_image"
ohos:height="match_content"
ohos:width="match_content"
ohos:background_element="$graphic:background_button"
ohos:left_margin="5vp"
ohos:padding="12vp"
ohos:text="缩放"
ohos:text_size="20vp"
ohos:top_margin="10vp">
</Button>
<Button
ohos:id="$+id:mirror_image"
ohos:height="match_content"
ohos:width="match_content"
ohos:background_element="$graphic:background_button"
ohos:left_margin="5vp"
ohos:padding="12vp"
ohos:text="镜像"
ohos:text_size="20vp"
ohos:top_margin="10vp"/>
</DirectionalLayout>
<Image
ohos:id="$+id:image"
ohos:height="match_content"
ohos:width="match_content"
ohos:image_src="$media:shanghai.png"
ohos:layout_alignment="horizontal_center"
ohos:top_margin="20vp">
</Image>
</DirectionalLayout>
```
在resource/base/graphic目录下添加background_button.xml
```xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:ohos="http://schemas.huawei.com/res/ohos"
ohos:shape="rectangle">
<corners
ohos:radius="40"/>
<solid
ohos:color="#e9e9e9"/>
</shape>
```
## slice 目录
在src/main/java/com/example/pictureoperation/slice目录下（不同的项目名称不同，官网例子为com/huawei/codelab）修改 MainAbilitySlice.java文件，继承AbilitySlice。
定义成员变量
类名和包名对应你的项目名，复制过来的项目代码需要对应修改
MainAbilitySlice.java
```java
package com.example.pictureoperation.slice;
import com.example.pictureoperation.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Button;
import ohos.agp.components.Component;
import ohos.agp.components.Image;
import ohos.agp.render.Canvas;
import ohos.agp.render.Paint;
import ohos.agp.render.PixelMapHolder;
import ohos.global.resource.NotExistException;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;
import ohos.media.image.ImageSource;
import ohos.media.image.PixelMap;
import ohos.media.image.common.PixelFormat;
import ohos.media.image.common.Rect;
import ohos.media.image.common.Size;
import java.io.IOException;
import java.io.InputStream;
/**
* 图像主页面
*/
public class MainAbilitySlice extends AbilitySlice {
private static final HiLogLabel LABEL_LOG = new HiLogLabel(3, 0xD001100, "MainAbilitySlice");
Image image;
PixelMap imagePixelMap;
Button whirlImageBtn;
Button cropImageBtn;
Button scaleImageBtn;
Button mirrorImageBtn;
private int whirlCount = 0;
private boolean isCorp = false;
private boolean isScale = false;
private boolean isMirror = false;
private float scaleX = 1.0f;
@Override
public void onStart(Intent intent) {
super.onStart(intent);
super.setUIContent(ResourceTable.Layout_ability_main);
initView();
}
private void initView() {
if (findComponentById(ResourceTable.Id_whirl_image) instanceof Button) {
whirlImageBtn = (Button) findComponentById(ResourceTable.Id_whirl_image);
}
if (findComponentById(ResourceTable.Id_crop_image) instanceof Button) {
cropImageBtn = (Button) findComponentById(ResourceTable.Id_crop_image);
}
if (findComponentById(ResourceTable.Id_scale_image) instanceof Button) {
scaleImageBtn = (Button) findComponentById(ResourceTable.Id_scale_image);
}
if (findComponentById(ResourceTable.Id_mirror_image) instanceof Button) {
mirrorImageBtn = (Button) findComponentById(ResourceTable.Id_mirror_image);
}
if (findComponentById(ResourceTable.Id_image) instanceof Image) {
image = (Image) findComponentById(ResourceTable.Id_image);
}
whirlImageBtn.setClickedListener(new ButtonClick());
cropImageBtn.setClickedListener(new ButtonClick());
scaleImageBtn.setClickedListener(new ButtonClick());
mirrorImageBtn.setClickedListener(new ButtonClick());
}
private class ButtonClick implements Component.ClickedListener {
@Override
public void onClick(Component component) {
int btnId = component.getId();
switch (btnId) {
case ResourceTable.Id_whirl_image:
// 旋转图片
whirlCount++;
isCorp = false;
isScale = false;
isMirror = false;
imagePixelMap = getPixelMapFromResource(ResourceTable.Media_shanghai);
image.setPixelMap(imagePixelMap);
break;
case ResourceTable.Id_crop_image:
// 剪裁图片
whirlCount = 0;
isCorp = !isCorp;
isScale = false;
isMirror = false;
imagePixelMap = getPixelMapFromResource(ResourceTable.Media_shanghai);
image.setPixelMap(imagePixelMap);
break;
case ResourceTable.Id_scale_image:
// 缩放图片
whirlCount = 0;
isCorp = false;
isScale = !isScale;
isMirror = false;
imagePixelMap = getPixelMapFromResource(ResourceTable.Media_shanghai);
image.setPixelMap(imagePixelMap);
break;
case ResourceTable.Id_mirror_image:
// 镜像图片
whirlCount = 0;
isCorp = false;
isScale = false;
isMirror = true;
imagePixelMap = getPixelMapFromResource(ResourceTable.Media_shanghai);
mirrorImage(imagePixelMap);
image.setPixelMap(imagePixelMap);
break;
default:
break;
}
}
}
private void mirrorImage(PixelMap pixelMap) {
scaleX = -scaleX;
image.addDrawTask(
new Component.DrawTask() {
@Override
public void onDraw(Component component, Canvas canvas) {
if (isMirror) {
isMirror = false;
PixelMapHolder pmh = new PixelMapHolder(pixelMap);
canvas.scale(
scaleX,
1.0f,
(float) pixelMap.getImageInfo().size.width / 2,
(float) pixelMap.getImageInfo().size.height / 2);
canvas.drawPixelMapHolder(
pmh,
0,
0,
new Paint());
}
}
});
}
/**
* 通过图片ID返回PixelMap
*
* @Param resourceId 图片的资源ID
* @Return 图片的PixelMap
*/
private PixelMap getPixelMapFromResource(int resourceId) {
InputStream inputStream = null;
try {
// 创建图像数据源ImageSource对象
inputStream = getContext().getResourceManager().getResource(resourceId);
ImageSource.SourceOptions srcOpts = new ImageSource.SourceOptions();
srcOpts.formatHint = "image/jpg";
ImageSource imageSource = ImageSource.create(inputStream, srcOpts);
// 设置图片参数
ImageSource.DecodingOptions decodingOptions = new ImageSource.DecodingOptions();
// 旋转
decodingOptions.rotateDegrees = 90 * whirlCount;
// 缩放
decodingOptions.desiredSize = new Size(isScale ? 512 : 0, isScale ? 384 : 0);
// 剪裁
decodingOptions.desiredRegion = new Rect(0, 0, isCorp ? 1024 : 0, isCorp ? 400 : 0);
decodingOptions.desiredPixelFormat = PixelFormat.ARGB_8888;
return imageSource.createPixelmap(decodingOptions);
} catch (IOException e) {
HiLog.info(LABEL_LOG, "IOException");
} catch (NotExistException e) {
HiLog.info(LABEL_LOG, "NotExistException");
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
HiLog.info(LABEL_LOG, "inputStream IOException");
}
}
}
return null;
}
@Override
public void onActive() {
super.onActive();
}
@Override
public void onForeground(Intent intent) {
super.onForeground(intent);
}
}
```
这里的 Media_shanghai 对应
最后导入一张 1024 * 768 的图片
## 效果展示
 正好我的手机正好是P40PRO，能用 谢谢楼主！！参考一下！！
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