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From: Bee on 11 Dec 2009 20:27
I am still working the first post using regions.
The second post is under study. Marching ants are nice but i have no idea
how to flip them when I flip the image.
The only problem with the first post is in regards to flipping the sprite
hoz or vert.
I am using StretchBlt to do this but here is what is happening.
Maybe this will trigger an oh yeah and have a simple answer.
When i flip the mask it looks correct.
When i flip the sprite the image flips but the image does not copy from an
image area into a black area so the black area remains and the image is
"clipped".
So there must be a simple fix that I cannot figure out.

From: Mike Williams on 12 Dec 2009 09:19


"Bee" <Bee(a)discussions.microsoft.com> wrote in message
news:6B144B30-2E74-4762-B572-E8E3B3144CF4(a)microsoft.com...

> I am still working the first post using regions. The second post
> is under study. Marching ants are nice but i have no idea
> how to flip them when I flip the image.

Actually flipping an irregular shaped sprite and mask image is fairly easy
but flipping the marching ants surrounding it requires a bit more thought,
because they are drawn using the Polygon API. One way is to add code to
effectively "flip" the POINTAPI data (apart from the original starting
position data item) so that the Polygon API draws a flipped copy of the
original polygon. This of course will cause the flipped polygon to be drawn
at the correct flipped shape but at the wrong position, so you also need to
offset the viewport origin just before your call to Polygon by a calculated
amount which is a function of the width of the sprite and the relative
position of the first data item in the POINTAPI array. You only need to flip
the polygon once of course, at the time that you flip the sprite and mask,
and thereafter you can use the "sprite and marching ants" animation (mouse
dragging) as normal. It's easy to get wrong though and it requires a bit of
thought, and often a bit of trial and error as well ;-) I'll post an
example for you when you are ready, but since you have said you are working
on the original PolyRegion code example (in which as far as I recall I did
not include a sprite flipping facility) and since the flipping of the sprite
and mask data appears to be currently the part of your question that you
most want answering, I'll concentrate on that first . . .

> The only problem with the first post is in regards to flipping
> the sprite hoz or vert. I am using StretchBlt to do this but here
> is what is happening. Maybe this will trigger an oh yeah and
> have a simple answer. When i flip the mask it looks correct.
> When i flip the sprite the image flips but the image does not
> copy from an image area into a black area so the black area
> remains and the image is "clipped". So there must be a simple
> fix that I cannot figure out.

I'm not really sure what you mean by that. If you posted your code, and
perhaps a screen dump of the sprite and mask both before and after flipping,
then I would be more easily able to see what you mean. If you're talking
about just a pixel or two then it might be that you are using slightly
incorrect parameters in the call to StretchBlt (in fact as I recall one of
the examples I posted had a "one pixel" problem, although I haven't checked
back through the group looking for it so I may not have done so). Also, of
course, it is far simpler if both the Sprite and Mask DCs are borderless,
otherwise you will have to mess about taking the borders into account. Here
is the code I am currently using myself for an X flip, which you can compare
to your own:

If flipX = True Then
StretchBlt picMask.hdc, spriteWide - 1, 0, -spriteWide, _
spriteHigh, picMask.hdc, _
0, 0, spriteWide, spriteHigh, vbSrcCopy
StretchBlt picSprite.hdc, spriteWide - 1, 0, -spriteWide, _
spriteHigh, picSprite.hdc, _
0, 0, spriteWide, spriteHigh, vbSrcCopy
End If

The only problem with the above code, which I intend to change, is that in
each case it flips the bitmap "in situ". In other words, in the call to
StretchBlt the destination DC and the source DC are the same. It does
actually work on both of the systems I am currently using, but personally
I've never been happy with using the same DC for both source and destination
in an operation which involves changing the entire contents of the bitmap
(as does a flip) because it relies too heavily on the details of underlying
StretchBlt algorithm and there is a chance that it might work on some
systems and fail on others (unless anybody knows if there is any MS
documentation to the contrary?). It is therefore probably better to use
StretchBlt to flip the bitmap into another similarly sized temporary bitmap
and then use a simple BitBlt to transfer the result from the temporary DC
back into the original DC, so (where picTemp is another PictureBox of the
same szie as the sprite and mask) you would have something like (air code!):

If flipX = True Then
StretchBlt picTemp.hdc, spriteWide - 1, 0, -spriteWide, _
spriteHigh, picMask.hdc, _
0, 0, spriteWide, spriteHigh, vbSrcCopy
BitBlt picMask.hdc, 0, 0, spriteWide, spriteHigh, _
picTemp.hdc, 0, 0, vbSrcCopy
StretchBlt picTemp.hdc, spriteWide - 1, 0, -spriteWide, _
spriteHigh, picSprite.hdc, _
0, 0, spriteWide, spriteHigh, vbSrcCopy
BitBlt picSprite.hdc, 0, 0, spriteWide, spriteHigh, _
picTemp.hdc, 0, 0, vbSrcCopy
End If

Anyway, post again if you are still having problems.

Mike


From: Bee on 12 Dec 2009 12:49
pardon my ignorance.
how do I post the images?

I hate to impose and email directly to you so I have avoided that thinking
that is not good form.
the code I have is dispersed through out my app so i am not sure how to do
that without introducing confusion to both of us.
as far as the image mask goes, it seems to flip OK.
the sprite image seems to fold itself over in the middle such that the black
area on the right is now overlayed on the left.
so an irregular shaped mask now become symmetrical about the center (based
on a horz flip). Same kind of thing happens on a vert flip.


From: Mike Williams on 12 Dec 2009 15:34
"Bee" <Bee(a)discussions.microsoft.com> wrote in message
news:2C6B4DE2-75C2-4E8C-A83B-3F33397E798A(a)microsoft.com...

> pardon my ignorance. how do I post the images?
> I hate to impose and email directly to you so I have
> avoided that thinking that is not good form

Ideally of course they should be hosted on the web somewhere and a link to
the file posted on the newsgroup, so that anyone else following the thread
can also see them (posting attachments to the newsgroup itself is frowned
upon, and doesn't always work anyway). If you have your own web page, or if
perhaps your ISP gives you a free web page facility, then you can host the
images on the page and post a link to it. In fact I think there some sites
out there that allow you to upload images or other files to their own
servers for free and they'll host them for you, although I've never used any
of them myself so I don't know how useful they are. Otherwise, if you can't
do any of those things then you can always email me. If you post your real
email address then I'll let you know mine, and then you can mail me the
images.

> the code I have is dispersed through out my app so
> i am not sure how to do that without introducing
> confusion to both of us.

You only need to post the relevant parts of the code, specifically just the
part that contains your two StretchBlt functions which flip the images (mask
and sprite) together with the declarations for any variables they use and
details of the values that are assigned to them, and of course details of
the size of the PictureBoxes involved.

> the sprite image seems to fold itself over in the middle such
> that the black area on the right is now overlayed on the left.
> so an irregular shaped mask now become symmetrical about
> the center (based on a horz flip).

Did you try my previous suggestion when I said that instead of using the
same hDC for both the source and destination DC in your call to StretchBlt
you should instead flip the sprite into an otherwise unused Autoredraw
PictureBox (picTemp) of the same size, and then blit the contents of picTemp
to the sprite picture box? Have you tried that? Also, have you properly
checked the values you are using in the StretchBlt call? Post the relevant
code sample.

Mike


From: Bee on 12 Dec 2009 19:01
Here is the flip routine. It works fine for all other image flip operations.
I am in the process of coding the last suggestion.

Public Function PictureBoxFlip(PicBox As PictureBox, ByVal eFlip As
eFlipEnum) As Boolean

' flip horz and/or flip vert
On Error GoTo PictureBoxFlipErr
Dim lW As Long
Dim lH As Long
Dim lRet As Long
Dim lX As Long
Dim lY As Long
Dim lWA As Long ' width adjust
Dim lHA As Long ' height adjjust

' make sure PicBox.ScaleMode = vbPixels ' pixels

lW = IIf((eFlip And eFlipHorizontal) = eFlipHorizontal, -1, 1)
lH = IIf((eFlip And eFlipVertical) = eFlipVertical, -1, 1)

'
lRet = SetStretchBltMode(PicBox.hdc, STRETCH_DELETESCANS) '
STRETCHMODE) '

If lW < 0 Then
lX = PicBox.ScaleWidth
lWA = 1
Else
lX = 0
End If
If lH < 0 Then
lY = PicBox.ScaleHeight
lHA = 1
Else
lY = 0
End If

PictureBoxFlip = (StretchBlt(PicBox.hdc, (lX - lWA), (lY - lHA), (lW *
PicBox.ScaleWidth), (lH * PicBox.ScaleHeight), PicBox.hdc, 0, 0,
PicBox.ScaleWidth, PicBox.ScaleHeight, vbSrcCopy) = 1)
PicBox.AutoRedraw = False
PicBox.AutoRedraw = True
PicBox.Refresh

PictureBoxFlipExit:
Exit Function

PictureBoxFlipErr:
Resume PictureBoxFlipExit

End Function 'PictureBoxFlip


"Mike Williams" wrote:

> "Bee" <Bee(a)discussions.microsoft.com> wrote in message
> news:2C6B4DE2-75C2-4E8C-A83B-3F33397E798A(a)microsoft.com...
>
> > pardon my ignorance. how do I post the images?
> > I hate to impose and email directly to you so I have
> > avoided that thinking that is not good form
>
> Ideally of course they should be hosted on the web somewhere and a link to
> the file posted on the newsgroup, so that anyone else following the thread
> can also see them (posting attachments to the newsgroup itself is frowned
> upon, and doesn't always work anyway). If you have your own web page, or if
> perhaps your ISP gives you a free web page facility, then you can host the
> images on the page and post a link to it. In fact I think there some sites
> out there that allow you to upload images or other files to their own
> servers for free and they'll host them for you, although I've never used any
> of them myself so I don't know how useful they are. Otherwise, if you can't
> do any of those things then you can always email me. If you post your real
> email address then I'll let you know mine, and then you can mail me the
> images.
>
> > the code I have is dispersed through out my app so
> > i am not sure how to do that without introducing
> > confusion to both of us.
>
> You only need to post the relevant parts of the code, specifically just the
> part that contains your two StretchBlt functions which flip the images (mask
> and sprite) together with the declarations for any variables they use and
> details of the values that are assigned to them, and of course details of
> the size of the PictureBoxes involved.
>
> > the sprite image seems to fold itself over in the middle such
> > that the black area on the right is now overlayed on the left.
> > so an irregular shaped mask now become symmetrical about
> > the center (based on a horz flip).
>
> Did you try my previous suggestion when I said that instead of using the
> same hDC for both the source and destination DC in your call to StretchBlt
> you should instead flip the sprite into an otherwise unused Autoredraw
> PictureBox (picTemp) of the same size, and then blit the contents of picTemp
> to the sprite picture box? Have you tried that? Also, have you properly
> checked the values you are using in the StretchBlt call? Post the relevant
> code sample.
>
> Mike
>
>
> .
>
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