在jpg圖像上繪製文本android

Question

我有一個jpg圖像作爲字節數組。我怎樣才能將這個字節數組轉儲爲JPG格式，然後在其上寫入canavas然後將其保存在SD卡上？

歡迎任何想法。謝謝。

Answer 1

使用BitmapFactory.decodeByteArray()獲得Bitmap，然後使用該位圖上創建一個Canvas，並繪製文本那裏。最後，通過使用Bitmap.compress()保存：

Bitmap bmp = BitmapFactory.decodeByteArray(myArray, 0, myArray.length).copy(Bitmap.Config.RGBA_8888, true); //myArray is the byteArray containing the image. Use copy() to create a mutable bitmap. Feel free to change the config-type. Consider doing this in two steps so you can recycle() the immutable bitmap. 
Canvas canvas = new Canvas(bmp); 
canvas.drawText("Hello Image", xposition, yposition, textpaint); //x/yposition is where the text will be drawn. textpaint is the Paint object to draw with. 

OutputStream os = new FileOutputStream(dstfile); //dstfile is a File-object that you want to save to. You probably need to add some exception-handling here. 
bmp.compress(CompressFormat.JPG, 100, os); //Output as JPG with maximum quality. 
os.flush(); 
os.close();//Don't forget to close the stream. 

Answer 2

1. 使用BitmapFactory
   1. 創建Canvas
   2. 上繪製text解碼字節數組
   3. Save你的位圖SD storage

希望這有助於。