在Delphi 2007中将具有透明度的位图保存为PNG [英] Save Bitmap with transparency to PNG in Delphi 2007

问题描述

我有一个具有透明度信息的Delphi位图(32Bit).我需要在保留透明度的同时将其转换并保存为PNG文件.

I have a Delphi bitmap (32Bit) that has transparency information. I need to convert and save it to a PNG file while preserving the transparency.

我目前拥有的工具是graphics32库，GR32_PNG(由Christian Budde设计)和PNGImage(由Gustavo daud设计).

The tools I currently have are the graphics32 Library, GR32_PNG (by Christian Budde), and PNGImage (by Gustavo daud).

做到这一点的最佳方法是什么?

What is the best way to do this?

我的位图中不仅只有一种颜色是透明的，还需要保留透明度不同的像素.

EDIT 1 : There is not just one color in my bitmap that's transparent but pixels with varying levels of transparency that needs to be preserved.

我通过将图像的背景设置为PNG来获得带有alpha信息的位图，而我只有空的alpha层.然后，我在上面写了抗锯齿的文本.然后，我保存位图.当使用gimp打开时，它会显示透明度，放大后您会看到抗锯齿的效果.

EDIT 2 : I am getting my bitmap with alpha information by setting the background of an image to a PNG I have with nothing but an empty alpha layer. Then I write anti-aliased text onto it. I then save the bitmap. When opened with gimp it show the transparency and upon zooming in you can see the effect of anti-aliasing.

推荐答案

我无法获得其他两个答案中的任何一个.他们可能会为他人工作，但这是我所做的.

I could not get either of the other two answer to work. They may work for others but here is what I did.

1. 我创建了具有透明度的位图.
2. 将其从Graphics 32库分配到TBitmap32.
3. 将其分配给Christian Budde的GR32_PNG for Graphics32的TPortableNetworkGraphics32
4. 调用了TPortableNetworkGraphics32.SaveToFile方法

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