Android圖片縮放以支持多種分辨率

Question

我已將我的遊戲編碼爲320x480，我認爲支持多種分辨率的最簡單方法是縮放最終圖片。你對此有何看法？以這種方式做cpu效率高嗎？

我把所有的圖像放在mdpi文件夾中，我將它在屏幕上縮放到緩衝區，然後縮放它以適合屏幕。所有的用戶輸入也將被縮放。

我有這兩個問題： - 你如何繪製一個位圖，沒有android自動縮放它 - 你如何縮放位圖？

Answer 1

我正在製作一款遊戲，並且我的目標是1280x800，並且我製作了所有圖片以匹配該分辨率。我第一次啓動遊戲時，我會縮小所有圖像以匹配當前分辨率，並使用縮放的圖像來真實地繪製遊戲。如果您使用的是SurfaceView，那麼在繪製圖像時不應該遇到縮放圖像的問題。只是爲了100％確定我將我的圖像保存在原始目錄中並從那裏加載它們。

要對位圖進行初始縮放，您只需在解碼位圖時使用BitmapFactory.Options來指示它的目標密度和實際要顯示的密度。

Answer 2

我在我的項目中多次遇到同樣的問題，每次都因缺乏時間（和懶惰）而感到滿意，我不滿足於最佳解決方案。但最近我發現了一些時間來打擊這個特殊問題。這是我的解決方案，我希望它也能幫助你。

Bitmap scaleWithAspectRatio(Bitmap image) 
     { 
      int imaheVerticalAspectRatio,imageHorizontalAspectRatio; 
      float bestFitScalingFactor=0; 
      float percesionValue=(float) 0.2; 

      //getAspect Ratio of Image 
      int imageHeight=(int) (Math.ceil((double) image.getHeight()/100)*100); 
      int imageWidth=(int) (Math.ceil((double) image.getWidth()/100)*100); 
      int GCD=BigInteger.valueOf(imageHeight).gcd(BigInteger.valueOf(imageWidth)).intValue(); 
      imaheVerticalAspectRatio=imageHeight/GCD; 
      imageHorizontalAspectRatio=imageWidth/GCD; 
      Log.i("scaleDownLargeImageWIthAspectRatio","Image Dimensions(W:H): "+imageWidth+":"+imageHeight); 
      Log.i("scaleDownLargeImageWIthAspectRatio","Image AspectRatio(W:H): "+imageHorizontalAspectRatio+":"+imaheVerticalAspectRatio); 

      //getContainer Dimensions 
      int displayWidth = getWindowManager().getDefaultDisplay().getWidth(); 
      int displayHeight = getWindowManager().getDefaultDisplay().getHeight(); 
      //I wanted to show the image to fit the entire device, as a best case. So my ccontainer dimensions were displayWidth & displayHeight. For your case, you will need to fetch container dimensions at run time or you can pass static values to these two parameters 

      int leftMargin = 0; 
      int rightMargin = 0; 
      int topMargin = 0; 
      int bottomMargin = 0; 
      int containerWidth = displayWidth - (leftMargin + rightMargin); 
      int containerHeight = displayHeight - (topMargin + bottomMargin); 
      Log.i("scaleDownLargeImageWIthAspectRatio","Container dimensions(W:H): "+containerWidth+":"+containerHeight); 

      //iterate to get bestFitScaleFactor per constraints 
      while((imageHorizontalAspectRatio*bestFitScalingFactor <= containerWidth) && 
        (imaheVerticalAspectRatio*bestFitScalingFactor<= containerHeight)) 
      { 
       bestFitScalingFactor+=percesionValue; 
      } 

      //return bestFit bitmap 
      int bestFitHeight=(int) (imaheVerticalAspectRatio*bestFitScalingFactor); 
      int bestFitWidth=(int) (imageHorizontalAspectRatio*bestFitScalingFactor); 
      Log.i("scaleDownLargeImageWIthAspectRatio","bestFitScalingFactor: "+bestFitScalingFactor); 
      Log.i("scaleDownLargeImageWIthAspectRatio","bestFitOutPutDimesions(W:H): "+bestFitWidth+":"+bestFitHeight); 
      image=Bitmap.createScaledBitmap(image, bestFitWidth,bestFitHeight, true); 

      //Position the bitmap centre of the container 
      int leftPadding=(containerWidth-image.getWidth())/2; 
      int topPadding=(containerHeight-image.getHeight())/2; 
      Bitmap backDrop=Bitmap.createBitmap(containerWidth, containerHeight, Bitmap.Config.RGB_565); 
      Canvas can = new Canvas(backDrop); 
      can.drawBitmap(image, leftPadding, topPadding, null); 

      return backDrop; 
     }