Added image development

Signed-off-by: Nwusongqing <wusongqing@huawei.com>

en/application-dev/media/image.md

+# Image Development
+
+## When to Use
+
+You can use image development APIs to decode images into pixel maps and encode the pixel maps into a supported format.
+
+## Available APIs
+
+For details about the APIs, see [js-apis-image.md](https://gitee.com/openharmony/docs/blob/master/en/application-dev/reference/apis/js-apis-image.md).
+
+## How to Develop
+
+### Full-Process Scenario
+
+The full process includes creating an instance, reading image information, reading and writing pixel maps, updating data, packaging pixels, and releasing resources.
+
+```js
+const Color = new ArrayBuffer(96); // Create a buffer to store image pixel data.
+let opts = { alphaType: 0, editable: true, pixelFormat: 4, scaleMode: 1, size: { height: 2, width: 3 } } // Image pixel data.
+
+// Create a PixelMap object.
+const Color = new ArrayBuffer(96);
+let opts = { alphaType: 0, editable: true, pixelFormat: 4, scaleMode: 1, size: { height: 2, width: 3 } }
+        image.createPixelMap(Color, opts, pixelmap => {
+            expect(pixelmap !== null).assertTrue();
+            console.info('TC_001-1 success');
+            done();
+        })
+// Read pixels.
+ pixelmap.readPixels(area,(data) => {
+ 	if(data !== null) {
+		var bufferArr = new Uint8Array(area.pixels);
+        var res = true;
+        for (var i = 0; i < bufferArr.length; i++) {
+			console.info('TC_021-1 buffer ' + bufferArr[i]);
+				if(res) {
+					if(bufferArr[i] == 0) {
+						res = false;
+                        console.info('TC_021-1 Success');
+                        expect(true).assertTrue();
+                        done();
+                        break;
+                        }
+                    }
+                }
+ 
+// Store pixels.
+const readBuffer = new ArrayBuffer(96);
+pixelmap.readPixelsToBuffer(readBuffer,() => {
+var bufferArr = new Uint8Array(readBuffer);
+var res = true;
+for (var i = 0; i < bufferArr.length; i++) {
+     if(res) {
+       if (bufferArr[i] !== 0) {
+          res = false;
+          console.info('TC_020-1 Success');
+          expect(true).assertTrue();
+          done();
+          break;
+          }
+       }
+    }
+    
+// Write pixels.
+pixelmap.writePixels(area,() => {
+    const readArea = { pixels: new ArrayBuffer(20), offset: 0, stride: 8, region: { size: { height: 1, width: 2 }, x: 0, y: 0 }}
+     pixelmap.readPixels(readArea,() => {
+         var readArr = new Uint8Array(readArea.pixels);
+         var res = true;
+         for (var i = 0; i < readArr.length; i++) {
+              if(res) {
+                  if (readArr[i] !== 0) {
+                      res = false;
+                      console.info('TC_022-1 Success');
+                      expect(true).assertTrue();
+                      done();
+                      break;
+                    }
+                 }
+            }
+  
+// Write pixels to the buffer.
+ pixelmap.writeBufferToPixels(writeColor).then(() => {
+     const readBuffer = new ArrayBuffer(96);
+     pixelmap.readPixelsToBuffer(readBuffer).then (() => {
+    	var bufferArr = new Uint8Array(readBuffer);
+     	var res = true;
+     	for (var i = 0; i < bufferArr.length; i++) {
+     		if(res) {
+     			if (bufferArr[i] !== i) {
+     				res = false;
+                    console.info('TC_023 Success');
+                    expect(true).assertTrue()
+                    done();
+                    break;
+                }
+            }
+       }
+
+// Obtain image information.
+pixelmap.getImageInfo( imageInfo => {
+     if (imageInfo !== null) {
+         console.info('TC_024-1 imageInfo is ready');
+         expect(imageInfo.size.height == 4).assertTrue();
+         expect(imageInfo.size.width == 6).assertTrue();
+         expect(imageInfo.pixelFormat == 4).assertTrue();
+         done();
+      } 
+ })
+
+// Release the PixelMap object.
+pixelmap.release(()=>{
+    expect(true).assertTrue();
+    console.log('TC_027-1 suc');
+    done();
+})
+
+// Create an image source (uri).
+const imageSourceApi = image.createImageSource(path);//'/data/local/tmp/test.jpg'
+
+// Create an image source (fd).
+const imageSourceApi = image.createImageSource(29);
+
+// Create an image source (data).
+const data = new ArrayBuffer(96);
+const imageSourceApi = image.createImageSource(data);
+
+// Release the image source.
+imageSourceApi.release(() => {
+    console.info('TC_044-1 Success');
+    })
+    
+// Encode the image.
+const imagePackerApi = image.createImagePacker();
+imagePackerApi.packing(imageSourceApi, packOpts, data => {
+    console.info('TC_062-1 finished');
+    expect(data !== null).assertTrue();
+    done();
+ })
+ 
+// Release the ImagePacker object.
+imagePackerApi.release();
+```
+
+### Decoding Scenario
+
+```js
+/data/local/tmp/test.jpg // Set the path for creating an image source.
+
+// Create an image source using a path.
+const imageSourceApi = image.createImageSource(path);//'/data/local/tmp/test.jpg'
+
+// Set parameters.
+let decodingOptions = {
+    sampleSize:1, // Sampling size of the thumbnail.
+    editable: true, // Whether the image can be edited.
+    desiredSize:{ width:1, height:2}, // Desired output size of the image.
+    rotateDegrees:10, // Rotation angle of the image.
+    desiredPixelFormat:2, // Decoded pixel format.
+    desiredRegion: { size: { height: 1, width: 2 }, x: 0, y: 0 }, // Region of the image to decode.
+    index:0// Image sequence number.
+    };
+    
+// Create a pixel map in callback mode.
+imageSourceApi.createPixelMap(decodingOptions, pixelmap => {
+    console.info('TC_050 createPixelMap ');
+    expect(pixelmap !== null ).assertTrue();
+    done();
+    })
+}  
+
+// Create a pixel map in promise mode.
+imageSourceApi.createPixelMap().then(pixelmap => {
+   console.info('TC_050-11 createPixelMap ');
+   expect(pixelmap !== null ).assertTrue();
+   done();
+})
+
+// Capture error information when an exception occurs during function invoking.
+catch(error => {
+    console.log('TC_050-11 error: ' + error);
+    expect().assertFail();
+    done();
+  })
+
+// Obtain the number of bytes in each line of pixels.
+pixelmap.getBytesNumberPerRow( num => {
+	console.info('TC_025-1 num is ' + num);
+	expect(num == expectNum).assertTrue();
+	done();
+})
+
+// Obtain the total number of pixel bytes.
+pixelmap.getPixelBytesNumber(num => {
+        console.info('TC_026-1 num is ' + num);
+        expect(num == expectNum).assertTrue();
+        done();
+    })
+
+// Obtain the pixel map information.
+ pixelmap.getImageInfo( imageInfo => {})
+ 
+// Print the failure information.
+console.info('TC_024-1 imageInfo is empty');
+expect(false).assertTrue()
+
+// Release the PixelMap object.
+pixelmap.release(()=>{
+            expect(true).assertTrue();
+            console.log('TC_027-1 suc');
+            done();
+        })    
+
+// Capture release failure information.
+catch(error => {
+            console.log('TC_027-1 error: ' + error);
+            expect().assertFail();
+            done();
+        })
+```
+
+### Encoding Scenario
+
+```js
+/data/local/tmp/test.png // Set the path for creating an image source.
+
+// Set the image source.
+ const imageSourceApi = image.createImageSource(path);//'/data/local/tmp/test.png'
+ 
+// Print the error message if the image source fails to be created.
+if (imageSourceApi == null) {
+   console.info('TC_062 create image source failed');
+   expect(false).assertTrue();
+   done();
+   }
+   
+// Create an image packer if the image source is successfully created.
+const imagePackerApi = image.createImagePacker();
+
+// Print the error information if the image packer fails to be created.
+if (imagePackerApi == null) {
+    console.info('TC_062 create image packer failed');
+    expect(false).assertTrue();
+    done();
+    }
+
+// Set encoding parameters if the image packer is successfully created.
+let packOpts = { format:["image/jpeg"], // The supported encoding format is jpg.
+                 quality:98 }// Image quality, which ranges from 0 to 100.
+
+// Encode the image.
+imagePackerApi.packing(imageSourceApi, packOpts)
+.then( data => {
+         console.info('TC_062 finished');
+         expect(data !== null).assertTrue();
+         done();
+        })
+             
+// Release the image packer after the encoding is complete.
+ imagePackerApi.release();
+ 
+// Obtain the image source information.
+imageSourceApi.getImageInfo(imageInfo => {
+     console.info('TC_045 imageInfo');
+     expect(imageInfo !== null).assertTrue();
+     done();
+   })
+   
+// Update incremental data.
+imageSourceIncrementalSApi.updateData(array, false, 0, 10,(error,data )=> {})
+
+```