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One (or several) more issue(s) with Aurigma.GraphicsMill.Bitmap: Case 1 (CMYK file and System.Drawing.Bitmap) Code:
var nativeBitmap = new System.Drawing.Bitmap("image_cmyk.jpg");
// nativeBitmap.PixelFormat is 8207 (CMYK) - OK
var bitmap = new Aurigma.GraphicsMill.Bitmap(nativeBitmap) // Faill
gives us Code:
Aurigma.GraphicsMill.UnsupportedPixelFormatException : The pixel format is not supported.
at Aurigma.GraphicsMill.PixelFormatUtils.TransformPixelFormatGdi(PixelFormat format)
at Aurigma.GraphicsMill.Bitmap..ctor(Bitmap bitmap)
looks like Aurigma is unable to understand CMYK pixel format with id 8207. Case 2 (Bitmap convertion) Code:
using (var bitmap = new Aurigma.GraphicsMill.Bitmap("image_cmyk.jpg"))
{
// bitmap.PixelFormat is Format32bppCmyk, OK
var nativeBitmap = bitmap.ToGdiPlusBitmap();
// nativeBitmap.PixelFormat is Format32bppArgb - Why??
using (var bitmap2 = new Aurigma.GraphicsMill.Bitmap(nativeBitmap))
{
bitmap.Draw(bitmap2, 0, 0, CombineMode.Copy); // crash
}
}
gives us Code:
Aurigma.GraphicsMill.UnsupportedPixelFormatException : The specified pixel format is not supported.
at Aurigma.GraphicsMill.GMException.ThrowManagedException(IntPtr unmanagedException)
at Aurigma.GraphicsMill.PipelineElement.RunPipeline()
at Aurigma.GraphicsMill.Pipeline.Run()
at Aurigma.GraphicsMill.Bitmap.Draw(Bitmap topBitmap, Int32 x, Int32 y, CombineMode combineMode)
And here looks like a different pixel formats issue. aklots attached the following image(s):
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The support of CMYK color space in the System.Drawing library (and underlying GDI+) is very limited and inconsistent. That's why Graphics Mill supports interoperability with the RGB pixel formats only. The ToGdiPlusBitmap method converts a bitmap to the Format32bppArgb pixel format as it allows us to be sure that the image will be processed by GDI+ correctly. So, actually, the exceptions you get are designed. I am curious why you need CMYK System.Drawing images? Actually, we have never seen the usage of GDI+ CMYK images in real applications except for detecting CMYK color space. |
Best regards, Fedor Skvortsov |
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Ok at first, I must say, I didn't expect ToGdiPlusBitmap to change image's pixel format. It could be usefull to have this information somewere here. Idea behind GDI+ CMYK came from two points: 1) it would be nice to work (apply transformation, effects) with all popular types of images (png, gif, jpeg) and pixel formats (32, 24, 8 pbb) without converting them to some common format, like Rgb24bpp. 2) some effects are external - implemented in native code and has no dependency on Aurigma.GraphicsMill.Bitmap. That is why Aurigma.GraphicsMill.Bitmap must be converted to GDI+ bitmap, passed to external library and than result should be applied to source Aurigma.GraphicsMill.Bitmap. For the last step I'm using Draw() method as a temporary solution. However idea is the same - interoperability with GDI+ without crashes.
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Hi, PixelFormat Enumeration does not contain CMYK formats, so I am not sure that converting to undocumented pixel format is a good idea. However, you can perform such conversion manually through access to pixel data: Code:
static Aurigma.GraphicsMill.Bitmap Convert(System.Drawing.Bitmap bitmap)
{
const int Format32bppCmyk = 0x200F;
const int PixelSize = 4;
if ((int)bitmap.PixelFormat != Format32bppCmyk)
return new Aurigma.GraphicsMill.Bitmap(bitmap);
var dstBitmap = new Aurigma.GraphicsMill.Bitmap(bitmap.Width, bitmap.Height, Aurigma.GraphicsMill.PixelFormat.Format32bppCmyk);
var rect = new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height);
var bits = bitmap.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadOnly, bitmap.PixelFormat);
try
{
var srcLine = bits.Scan0;
var dstLine = dstBitmap.Scan0;
unsafe
{
for (int i = 0; i < bitmap.Height; i++)
{
var src = (byte*)srcLine;
var dst = (byte*)dstLine;
for (int j = 0; j < bitmap.Width; j++)
{
dst[0] = src[3];
dst[1] = src[2];
dst[2] = src[1];
dst[3] = src[0];
dst += PixelSize;
src += PixelSize;
}
srcLine += bits.Stride;
dstLine += dstBitmap.Stride;
}
}
}
finally
{
bitmap.UnlockBits(bits);
}
return dstBitmap;
}
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Best regards, Eugene Kosmin The Aurigma Development Team |
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Hi Eugene, Quote:PixelFormat Enumeration does not contain CMYK formats, so I am not sure that converting to undocumented pixel format is a good idea. ok, good point. Quote:However, you can perform such conversion manually through access to pixel data Thank you for a nice solution! Actually now I'm thinking about even more simpler solution, for my case. I could pass image data to the external, graphics mill independent, component using System.Drawing.Imaging.BitmapData instead of System.Drawing.Bitmap. This way I'll have no conversion at all, only passing pointer. By the way, do you have an extension method like this: Code: public static System.Drawing.Imaging.BitmapData AsBitmapData(this Aurigma.GraphicsMill.Bitmap bitmap)
{
var bitmapData = new BitmapData
{
Scan0 = bitmap.Scan0,
Stride = bitmap.Stride,
Width = bitmap.Width,
Height = bitmap.Height,
PixelFormat = bitmap.PixelFormat,
};
return bitmapData;
}
?
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Rank: Advanced Member
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Quote:By the way, do you have an extension method like this: No, we don’t have. Quote:I could pass image data to the external, graphics mill independent, component using System.Drawing.Imaging.BitmapData instead of System.Drawing.Bitmap. This way I'll have no conversion at all, only passing pointer. Yes, you are right. Pixel layouts are the same for RGB formats, so you can just create BitmapData without copy. But for CMYK format layouts are different, so you need to swap channels CMYK <-> KYMC. |
Best regards, Eugene Kosmin The Aurigma Development Team |
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Rank: Newbie
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Posts: 7
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Ok, I'll keep in mind that. Thanks a lot guys!
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