ImageLibEx library

[klaus]

Hi Andrew,
For the 3 point arc, have a look here post @22
http://www.basic4ppc.com/forum/quest...int-arc-2.html

Best regards.

[sitajony]

Hi, I used AlphaBlend() in coredll but it return an image with a black border so I would try with this library but I don't understand how use it? It return always an error like "Exception", "NotImplemented..." Is right that we can finally draw an image correctly with the Alpha value from a PNG Image on an image? If yes how do it?
Thanks for your replies!

[agraham]

Are you trying so use ReadAlphaData on a device? From a comment in the ImageAlpha.sbp demo

' make the alpha data file on the desktop, throws a NotImplemented exception on the device

That demo shows you how to do it. The alpha data file must be made on the desktop as devices can't read alpha values in png files.

[sitajony]

But how do by example W**bar Ad*ance Des*top and some others softwares? There's surely an other soluce to get the alpha value... I'm searching...

[agraham]

They are probably not .NET apps and have their own native code functions to do it. The Compact Framework does not support alpha values in bitmaps.

[sitajony]

I found how get the alpha value... In fact I use OpenNETCF and it works great...
This is an example with transparency by pixel and transparency by Alpha value:

It's a really better...
Not computer needed, just type withalpha((Bitmap) Support, (String) Image File, (Int) X, (Int) Y, (Int) Width, (Int) Height) and it return the pasted image with the gif/png...
Hum I don't know if I can post my lib coz it's not really my lib, I use an other API (in OpenNETCF) so I don't know...

[agraham]

Version 2.2 now posted includes an additional DrawerEx method. DrawArc3 takes three points, calculates the centre and radius of the circle that encloses all three points and draws the arc of that circle that connects those three points. Some parts of the algorithm used bear a remarkable similarity to that in a Basic4ppc program previously posted by Klaus who also supplied the raw equations to implement.

[ceaser]

Thank you very much Agraham

[klaus]

Ai Andrew,

I have noticed that with the RotateHQ function there are pixels that don't have the right fillcolor.

The attached program and the pictures below show the problem.

This doesn't happen with the RotateFast function.

Could you please have a look at it.

Thank you in advance and Best regards.

[agraham]

It's a transparency issue. Because RotateHQ achieves the higher quality by a weighted interpolation of the colours of the four original pixels that cover the block where the rotated pixel is to be positioned and because the colour values are integers and the weighting factors are not there will be a final rounding effect on the final colour value. In this case that is varying the needle background colour from the transparent value that you are using.

In this case you could minimise the effect by chopping off the white extension to the needle on the bitmap and calulating an appropriate x and y offset to position the rotated needle at the centre of the dial. Using a less obvious transparent colour, such as mid-grey, might also be beneficial.