Keep your forms in shape

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<EM> On the 8th day,&nbsp;he 
created win32 api, and saw it was good.</EM> <BR><EM>~Holy Bible, book of Cakkie, 
chapter 1, vers 8</EM> 
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<P>So we all know that we have API's, know we just need to know how to use 
them.</P>
<P>I'm going to explain the region API's wich can give us the power to reshape 
every window, or everything that has a window handle (like a picturebox).</P>
<P><EM>- In the beginning there was nothing, as far as the eye can see, nothing, 
nada, njet, rien, niets, nothing.<BR>- Sir, really nothing?<BR>~Urbanus</EM></P>
<P>Lets start with the begin. When we want to create regions, we have a variety 
of API's to use. The most important are <STRONG>CreateRectRgn</STRONG>: creates 
a rectangular region<BR><STRONG>CreateRoundRectRgn</STRONG>: creates a rounded 
rectangular region<BR><STRONG>CreateEllipticRgn</STRONG>: creates a elliptical 
region<BR><STRONG>CreatePolygonRgn</STRONG>: create a region from an array of 
points</P>
<P>The first&nbsp;3 (Rect, RoundRect and Elliptic) all take the same parameters. 
The first 2 are the X and Y coordinates specifying the upper-left corner of the 
region, the&nbsp;next 2 are the X and Y coordinates specifying the lower-right 
corner or the region.</P>
<P>The CreatePolygonRgn takes following parameters<BR>The first is&nbsp;the 
pointer to an array of the type POINTAPI<BR>The second is the number of points 
in that array<BR>The last is the fillmode, which can be obtained by the 
<STRONG>GetFillMode </STRONG>API</P>
<P>Once we created a region, we can use that to shape our form (or picturebox or 
whatever, I'm only using forms here for breverity's sake)<BR>This is done by the 
SetWindowRgn API, which takes the form's hWnd, the region and a boolean 
specifying the form needs to be repainted.<BR><BR>Once that is done, the form 
has the shape&nbsp;defined by the region.</P>
<P><EM>- Is this the end?<BR>- No, it is&nbsp;just the beginning<BR>~Arnold 
Swarzenegger</EM></P>
<P>Now we can have a form of almost any shape, but it doesn't end here. We can 
also combine regions, what gives us the possibility to create even complexer 
regions. This is done with the CombineRgn API. This function takes 4 parameters, 
the first is the region wich will receive the result of the combine operation. 
The second is the first region that needs to be combined, the third is the 
second region to combine. The last parameter is the method we want to use to 
combine. That can be one of the following:<BR><STRONG>RGN_AND </STRONG>= 1 : 
gives the region which is both in the first and the second 
region<BR><STRONG>RGN_COPY </STRONG>= 5 : copies the first 
region<BR><STRONG>RGN_DIFF </STRONG>= 4 : gives the regions which are in region1 
but not in region2<BR><STRONG>RGN_OR </STRONG>= 2 : gives the regions which are 
in region1 or in region2<BR><STRONG>RGN_XOR </STRONG>= 3 ; gives the regions 
which are in region1 or in region2, but not in both</P>
<P>You must keep in mind that the receiving region already exists (by using the 
CreateRectRgn for example).</P>
<P>You can also combine regions by using the <STRONG>CreatePolyPolygonRgn 
</STRONG>function, which creates a region existing out several Polygon regions. 
This way you can combine several Polygonregions in one call. However, I like 
using the CombineRgn because it's simplicity.</P>
<P><EM>This isn't Mission Difficult, this is Mission Impossible, Mission 
Difficult should be a walk in the park for you<BR>~Gene Hackman</EM></P>
<P><U>With this tutorial are 3 examples</U>. </P>
<P><STRONG>The region example </STRONG>shows the general use of the api's 
described above. Just click one of the buttons and look what happens to 
the&nbsp;form.</P>
<P><STRONG>The 8ball example </STRONG>is a simple 'Magic 8 Ball' program, wich 
really looks like an 8 ball. It also shows how to move a form when the titlebar 
isn't visible. In order to get it working, you must shake the ball (that is move 
the form around for a couple of seconds)</P>
<P><STRONG>The Bill example </STRONG>is my favorite. It creates a region from a 
bitmap. It gives a background color (in this case green) which will be left out 
of the region. This way, you can get a form that is so odd-shaped it would take 
hours to code it yourself. This also supports moving the form (which has no 
border) and makes the form topmost. You will find out why I called it Bill the 
second you run it.</P>
<P><EM>What has become of this world?<BR>~Beatrix (Final Fantasy IX)</EM></P>
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