Generating Thumbnails

Is there any special API/functions for generating thumbnails or everybody uses StrechBlt/PaintPicture for doing so?

There isn't any difference, thumbnails are resized

Only thing you can do is anti-aliasing to save quality...

Here's some code I found to interpolate an image:

Code:

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    For y = 0 To Pic.Height Step ((Pic.Height / Resized.Height) * 15) - 1
        For x = 0 To Pic.Width Step ((Pic.Width / Resized.Width) * 15) - 1
            Dim cRed, cBlue, cGreen
            For sX = x To (x + ((Pic.Width / Resized.Width) * 15)) Step 15
                For sY = y To (y + ((Pic.Height / Resized.Height) * 15)) Step 15
                    RGBfromLONG (GetPixel(Pic.hdc, sX / 15, sY / 15))
                    cRed = (cRed + rRed) / 2
                    cBlue = (cBlue + rBlue) / 2
                    cGreen = (cGreen + rGreen) / 2
                Next sY
            Next sX
            SetPixel Resized.hdc, rX / 15, rY / 15, RGB(cRed, cGreen, cBlue)
            rX = rX + 15
        Next x
       
        rY = rY + 15
        rX = 0
    Next y
   
    Resized.Refresh

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Now the function RGBFromLong:

Code:

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Private Function RGBfromLONG(LongCol As Long)
    'Get The Red, Blue And Green Values Of A Colour From The Long Value
   
    rRed = LongCol And 255
    rGreen = (LongCol And 65280) \ 256
    rBlue = (LongCol And 16711680) \ 65535
End Function

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Oh, there's 3 more variables you must declare (in the Declarations part of the code, before all the other functions) :

Code:

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Dim rRed As Byte
Dim rBlue As Byte
Dim rGreen As Byte

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That's it. Make sure you have the SetPixel and GetPixel APIs declared. The original image is Pic and the resized image is Resized. Sorry for having no comments, but that's how I found the function. And if it doesn't work, reply back, because I haven't tested it!

I am sory to ask this question again, but I still have no answer for this one:

Have any one of you ever tried using PaintPicture or StrechBlt on a child window. I cannot seem to make it work when I call it in the form resize event. The child window and the Mdi window are from two different applications. I am setting the child window to its mdi parent through a api call. If you can't understand the question, please post a message so that I can calrify further.

Oops!
Sorry for the trouble, but it was a simple case of setting the autoredraw property to true.

Sorry again