PDFBox - 帶梯度的矩形

Question

我正嘗試使用Java中的PDFBox庫創建pdf。我必須使用漸變創建矩形，但我不知道如何以及什麼都找不到。任何人都可以幫助我嗎？

Answer 1

找到這個例子。看看它是否適合你

COSDictionary fdict = new COSDictionary(); 

    fdict.setInt(COSName.FUNCTION_TYPE, 2); // still not understaning that... 

    COSArray domain = new COSArray(); 
    domain.add(COSInteger.get(0)); 
    domain.add(COSInteger.get(1)); 

    COSArray c0 = new COSArray(); 
    c0.add(COSFloat.get("0.64176")); 
    c0.add(COSFloat.get("0.72588")); 
    c0.add(COSFloat.get("0.78078")); 

    COSArray c1 = new COSArray(); 
    c1.add(COSFloat.get("0.57176")); 
    c1.add(COSFloat.get("0.62588")); 
    c1.add(COSFloat.get("0.70078")); 

    fdict.setItem(COSName.DOMAIN, domain); 
    fdict.setItem(COSName.C0, c0); 
    fdict.setItem(COSName.C1, c1); 
    fdict.setInt(COSName.N, 1); 

    PDFunctionType2 func = new PDFunctionType2(fdict); 

    PDShadingType2 axialShading = new PDShadingType2(new COSDictionary()); 

    axialShading.setColorSpace(PDDeviceRGB.INSTANCE); 
    axialShading.setShadingType(PDShading.SHADING_TYPE2); 

    COSArray coords1 = new COSArray(); 
    coords1.add(COSInteger.get(0)); 
    coords1.add(COSInteger.get(0)); 
    coords1.add(COSInteger.get(850)); // size of my page 
    coords1.add(COSInteger.get(600)); 

    axialShading.setCoords(coords1); // so this sets the bounds of my gradient 
    axialShading.setFunction(func); // and this determines all the curves etc? 

    CStr.shadingFill(axialShading); // where CStr is a ContentStream for my PDDocument