改善圖像旋轉質量

Question

當前我正在使用此代碼（我發現here）在Java中旋轉圖像。代碼運行良好，但我對旋轉圖像的質量不滿意。你們可以幫我改進它，或者你能推薦一個好的Java圖像旋轉庫嗎？

public static BufferedImage rotate(BufferedImage image, float angle) 
{ 
    float radianAngle = (float) Math.toRadians(angle) ; 

    float sin = (float) Math.abs(Math.sin(radianAngle)); 
    float cos = (float) Math.abs(Math.cos(radianAngle)); 

    int w = image.getWidth() ; 
    int h = image.getHeight(); 

    int neww = (int) Math.round(w * cos + h * sin); 
    int newh = (int) Math.round(h * cos + w * sin); 

    GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment(); 
    GraphicsDevice gd = ge.getDefaultScreenDevice(); 
    GraphicsConfiguration gc = gd.getDefaultConfiguration(); 

    BufferedImage result = gc.createCompatibleImage(neww, newh, Transparency.TRANSLUCENT); 
    Graphics2D g = result.createGraphics(); 

    //--------------------------------------------------------------------- 
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 

    g.translate((neww-w)/2, (newh-h)/2); 
    g.rotate(radianAngle, w/2, h/2); 
    //--------------------------------------------------------------------- 

    g.drawRenderedImage(image, null); 
    g.dispose(); 

    return result; 
} 

Answer 1

下面是完整的工作代碼：

public static BufferedImage rotate(BufferedImage image, float angle) 
{ 
    float radianAngle = (float) Math.toRadians(angle) ; 

    float sin = (float) Math.abs(Math.sin(radianAngle)); 
    float cos = (float) Math.abs(Math.cos(radianAngle)); 

    int w = image.getWidth() ; 
    int h = image.getHeight(); 

    int neww = (int) Math.round(w * cos + h * sin); 
    int newh = (int) Math.round(h * cos + w * sin); 

    GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment(); 
    GraphicsDevice gd = ge.getDefaultScreenDevice(); 
    GraphicsConfiguration gc = gd.getDefaultConfiguration(); 

    BufferedImage result = gc.createCompatibleImage(neww, newh, Transparency.TRANSLUCENT); 
    Graphics2D g = result.createGraphics(); 

    //-----------------------MODIFIED-------------------------------------- 
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON) ; 
    g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC) ; 
    g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY) ; 

    AffineTransform at = AffineTransform.getTranslateInstance((neww-w)/2, (newh-h)/2); 
    at.rotate(radianAngle, w/2, h/2); 
    //--------------------------------------------------------------------- 

    g.drawRenderedImage(image, at); 
    g.dispose(); 

    return result; 
}