clone a bitmap??? any help appreciated

Options

Previous Topic Next Topic

keesjalink User Profile View All Posts by User View Thanks		#1 Posted : Monday, March 22, 2004 6:12:00 AM(UTC)
Rank: Member Groups: Member Joined: 3/22/2004(UTC) Posts: 18		Dear All, I (newby) try to do make a routine in VB6 which allows the user to adjust intensity and contrast of a bitmap (8bppgray) by typing in B and C values in a textbox. If I do: Code: `BitmapViewer1.Bitmap.ColorAdjustment.BrightnessContrast B, C` then each time the textbox changes, the contrast is adjusted in a cumulative way (the user first tries B=20, but thinks it is not enough, so he increases to B=25, than the effect is much more than 25). I tried to remedy this by reverting to a copy of the original each time the textbox value changes: first save a copy: Code: `dim BitmapBu as bitmap '(global, Bu=backup) Set Bitmap1Bu = BitmapViewer1.Bitmap.Clone` then in the routine that adjusts the contrast, first revert to saved original, and then apply the new B,C values on that original. Code: `Set BitmapViewer1.Bitmap = Bitmap1Bu BitmapViewer1.Bitmap.ColorAdjustment.BrightnessContrast B,C` However, it still works cumulative....?????? Why? How do I solve this? Edited by user Monday, December 24, 2007 6:06:18 PM(UTC) \| Reason: Not specified

Andrew User Profile View All Posts by User View Thanks		#2 Posted : Monday, March 22, 2004 12:58:00 PM(UTC)
Rank: Advanced Member Groups: Member, Administration Joined: 8/2/2003(UTC) Posts: 876 Thanks: 2 times Was thanked: 27 time(s) in 27 post(s)		Dear Kees, When you write Code: `Set object1 = object2` you just put a reference of object2 to object1 (not a copy). This way both these variables points to the same object. If you need to make it copying back to the BitmapViewer, you should use Clone method again: Set objBitmapViewer1.Bitmap = Bitmap1Bu.Clone Edited by user Monday, December 24, 2007 6:06:30 PM(UTC) \| Reason: Not specified

Andrew User Profile View All Posts by User View Thanks		#3 Posted : Monday, March 22, 2004 1:08:00 PM(UTC)
Rank: Advanced Member Groups: Member, Administration Joined: 8/2/2003(UTC) Posts: 876 Thanks: 2 times Was thanked: 27 time(s) in 27 post(s)		There is an alternative way: Code: `Dim objBitmapBu As Bitmap Set objBitmapBu = BitmapViewer1.Bitmap.Clone objBitmapBu.ApplyInPlace = False` Then in code you write just: Code: `Set objBitmapViewer1.Bitmap = objBitmapBu.ColorAdjustment.BrightnessContrast (B, C)` The idea of this code is the following: when you disable ApplyInPlace property, the behaviour of the effects is changed. Instead of applying it in-place, Bitmap returns modified copy. In other word, Graphics Mill automatically clones bitmap and applies effect on copy. The only think you should remember when setting ApplyInPlace to False is that all methods which should change the bitmap will return changed copy instead of changing the bitmap itself. So if you need to do something like this, do not forget to change this property back to True. Edited by user Monday, December 24, 2007 6:06:48 PM(UTC) \| Reason: Not specified

keesjalink User Profile View All Posts by User View Thanks		#4 Posted : Monday, March 22, 2004 3:07:00 PM(UTC)
Rank: Member Groups: Member Joined: 3/22/2004(UTC) Posts: 18		Thanks. problem solved (and fast!) (by the way, why do you guys always write "objBitmapViewer1.Bitmap" instead of just "BitmapViewer1.Bitmap"? Is that a convention?) Kees

Andrew User Profile View All Posts by User View Thanks		#5 Posted : Monday, March 22, 2004 3:26:00 PM(UTC)
Rank: Advanced Member Groups: Member, Administration Joined: 8/2/2003(UTC) Posts: 876 Thanks: 2 times Was thanked: 27 time(s) in 27 post(s)		There is a convension to add type prefix to the variable name to VB (and especially VBScript) code. It makes code more clear and understandable. However in case of BitmapViewer, name BitmapViewer1 is generated by VB when you put control on form. So appending obj prefix in this case is just a habit...

keesjalink User Profile View All Posts by User View Thanks		#6 Posted : Wednesday, March 24, 2004 7:41:00 PM(UTC)
Rank: Member Groups: Member Joined: 3/22/2004(UTC) Posts: 18		Actually, if I use Andrews solution mentioned above, a subtle thing goes very wrong (probably because I still don't understand exactly what happens). after cloning my 8bppgray image Code: `Set Bitmap1Bu = BitmapViewer1.Bitmap.Clone` I wrote: Code: `private sub cmdBrightContrast_Changed Bitmap1Bu.ApplyInPlace = False Set BitmapViewer1.Bitmap = Bitmap1Bu.ColorAdjustment.BrightnessContrast(B,C) Bitmap1Bu.ApplyInPlace = True end sub` then this works nicely FOR THIS BITMAP. But after I open another image into the same bitmapviewer: Code: `Private Sub cmdLoadIntens_Click() BitmapViewer1.Bitmap.LoadFromFile ("whatever.bmp") BitmapViewer1.Bitmap.Data.ConvertTo8bppGrayscale Set Bitmap1Bu = BitmapViewer1.Bitmap.Clone '---again setting the clone End Sub` this new image is displayed correctly, and it can also be altered for Brightness/contrast, but as soon as I ask (somewhere else in my code) whether it is 8bbpgray it appears to be 24bit. Is this because there is still a reference to the first opened image? (ask for full code if you need it). Thanks, Kees Edited by user Monday, December 24, 2007 6:07:10 PM(UTC) \| Reason: Not specified

Andrew User Profile View All Posts by User View Thanks		#7 Posted : Wednesday, March 24, 2004 8:26:00 PM(UTC)
Rank: Advanced Member Groups: Member, Administration Joined: 8/2/2003(UTC) Posts: 876 Thanks: 2 times Was thanked: 27 time(s) in 27 post(s)		It is possible you disable ApplyInPlace for BitmapViewer1.Bitmap somewhere, so line BitmapViewer1.Bitmap.Data.ConvertTo8bppGrayscale does not convert the bitmap itself. If it won't help, please submit case with full code. Edited by user Friday, May 23, 2008 4:15:13 PM(UTC) \| Reason: Not specified

Users browsing this topic

Forum Jump

You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.