"Herfried K. Wagner [MVP]" <hirf-spam-me-here@gmx.at> wrote in message
news:OFdrBOPWGHA.1348@TK2MSFTNGP05.phx.gbl...
> "Galen Somerville" <galen@community.nospam> schrieb:
>>> DrawReversibleFrame()
>>
>> That would be a real kludge. DrawReversibleLine would do for the actual
>> marker line.
>>
>> But what about the text? Also the user now has the ability to use a
>> specific color for the markers.
>
> Unfortunately this is a limitation of GDI+ which 'System.Drawing' is based
> on.
>
> --
> M S   Herfried K. Wagner
> M V P  <URL:http://dotnet.mvps.org/>
> V B   <URL:http://classicvb.org/petition/>

"AMercer" <AMer***@discussions.microsoft.com> wrote in message
news:27BFFD85-C929-4DFC-872A-E94943C2CFED@microsoft.com...
> how about this.  have the fixed trace be one bitmap drawn first and have a
> changing overlay bitmap that has a transparent background drawn on top of
> the
> trace.
>
> make a bitmap (bmOverlay) of the same size as the fixed drawing (the
> trace).
> Make this bitmap transparent for black via
>  bmOverlay.MakeTransparent(Color.Black)
> when an update happens, clear the bmOverlay to black, rebuild all its
> vertical lines and text as you wish (location, color, etc).  When it is
> time
> to paint, paint the fixed bitmap first, then bmOverlay.
>

"AMercer" <AMer***@discussions.microsoft.com> wrote in message
news:6529E615-5A51-40D9-B2B8-B6ACEED41F3F@microsoft.com...
>>  My user control has a "permanent" bitmap (Bmp) which I
>> believe is continually painted by
>>
>>     Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
>>         MyBase.OnPaint(e)
>>         e.Graphics.DrawImage(Bmp, e.ClipRectangle, e.ClipRectangle,
>> GraphicsUnit.Pixel)
>>     End Sub
>
> "Continually" painted?  Do you mean that the trace bitmap needs repainting
> because it is being updated, maybe moving horizontally as time passes?  If
> so, don't you want the overlay to move with it?  "Continually" kind of
> throws
> me.
>
>> When I want to clear the bitmap I use the BackColor property. The first
>> use
>> of this property sets up the permanent bitmap and sets a flag. Subsequent
>> calls see the flag and skip the setup and just clears the bitmap to the
>> proper color.
>
> Still thrown by continually and now permanent above.
>
>> Question. To paint the bmOverlay would I just set a flag then have an If
>> statement in the above OnPaint event?
>
> I ran one test, and painting (via DrawImage) the overlay bitmap after the
> trace bitmap works fine.  A flag that governs whether the overlay is
> visible
> or not sounds like a good idea to me.  Just to be complete, my test
> program
> did not use OnPaint.  Instead, when it had an updated bitmap it did
> Form1.Invalidate(), and painting took place as follows:
>
>  Private Sub Form1_Paint(ByVal sender As Object, ByVal e As
> PaintEventArgs) _
>  Handles MyBase.Paint
>        e.Graphics.DrawImage(bmImage, 0, 0)
>        e.Graphics.DrawImage(bmOverlay, 0, 0)
>  End Sub
>
> I don't think this difference is of consequence.

"Galen Somerville" <galen@community.nospam> wrote in message
news:%23OXs%23fYWGHA.1220@TK2MSFTNGP02.phx.gbl...
>
> "AMercer" <AMer***@discussions.microsoft.com> wrote in message
> news:6529E615-5A51-40D9-B2B8-B6ACEED41F3F@microsoft.com...
>>>  My user control has a "permanent" bitmap (Bmp) which I
>>> believe is continually painted by
>>>
>>>     Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
>>>         MyBase.OnPaint(e)
>>>         e.Graphics.DrawImage(Bmp, e.ClipRectangle, e.ClipRectangle,
>>> GraphicsUnit.Pixel)
>>>     End Sub
>>
>> "Continually" painted?  Do you mean that the trace bitmap needs
>> repainting
>> because it is being updated, maybe moving horizontally as time passes?
>> If
>> so, don't you want the overlay to move with it?  "Continually" kind of
>> throws
>> me.
>>
>>> When I want to clear the bitmap I use the BackColor property. The first
>>> use
>>> of this property sets up the permanent bitmap and sets a flag.
>>> Subsequent
>>> calls see the flag and skip the setup and just clears the bitmap to the
>>> proper color.
>>
>> Still thrown by continually and now permanent above.
>>
>>> Question. To paint the bmOverlay would I just set a flag then have an If
>>> statement in the above OnPaint event?
>>
>> I ran one test, and painting (via DrawImage) the overlay bitmap after the
>> trace bitmap works fine.  A flag that governs whether the overlay is
>> visible
>> or not sounds like a good idea to me.  Just to be complete, my test
>> program
>> did not use OnPaint.  Instead, when it had an updated bitmap it did
>> Form1.Invalidate(), and painting took place as follows:
>>
>>  Private Sub Form1_Paint(ByVal sender As Object, ByVal e As
>> PaintEventArgs) _
>>  Handles MyBase.Paint
>>        e.Graphics.DrawImage(bmImage, 0, 0)
>>        e.Graphics.DrawImage(bmOverlay, 0, 0)
>>  End Sub
>>
>> I don't think this difference is of consequence.
>
> Yes it is rather confusing. The trace display is Heart sounds and is an
> oscilloscope type of display. That is, every few seconds lines are drawn
> to connect the next 4 pixels horizontally. Since we show a gap, typically
> 5 to 10 pixels wide, we have to also have to redraw the existing 4 pixels
> beyond the gap to the background color.
>
> Originally I was getting flickering and other display problems. In a
> stroke of genious, I added a module to the usercontrol and moved certain
> declarations to this module as Public. Specifically g as Graphics, p as
> Pen, f as Font and Bmp as bitmap. This is what I meant by "permanent".
>
> Now the display is as solid as a rock. Continually is probably the wrong
> wording. I don't make a change an then invalidate. I just make the
> changes. As I understand it, invalidate means do a Paint on next vertical
> sweep. I further understand that the overides OnPaint means Paint on every
> vertical sweep.
>
> GalenS
>
>

"Galen Somerville" <galen@community.nospam> wrote in message
news:eAoxI7MWGHA.3492@TK2MSFTNGP05.phx.gbl...
> In my opinion, one of the worst failures of Net (VB2005 Pro) was not
> providing an XOR line draw feature, as in VB6.
>
> A major feature of my app is allowing the user to draw Markers (vertical
> lines) on a trace so they can measure the time difference between markers.
>
> Once they click on a desired location, on a trace, arrow buttons are
> provided so they can move the marker to an exact location. With xor, I
> just redraw the current marker to make it disappear then draw a new marker
> one pixel away. No sweat in VB6.
>
> I have put a screen shot of a typical trace with markers on my web site
> under "Private" then click on "Marker display" "screen shot"
> http://home.surewest.net/galen/index.html
>
> I would appreciate any guidance I can get.
>
> The traces are on a bitmap which is contained in a User Control. I thought
> of drawing the marker on a copy of the bitmap. To move the marker I would
> toss the copy and draw the new marker on a new copy of the original
> bitmap. This, of course, would complicate my User Control.
>
> Also there can be up to four markers displayed. If I move one and toss the
> bitmap copy, I not only have to draw the new marker but I have to redraw
> the other three which didn't move.
>
> As you can see on the screen shot, a marker also shows some text (time
> difference between markers). This means I can't just read in a vertical
> set of pixels and later restore them as the marker is moved.
>
> I could read a vertical rectangle which would be as wide as the worst case
> text size.
>
> Also, as the marker nears the right edge of the screen, the text is placed
> to the left of the marker.
>
> H E L P
>
> GalenS
>
>

"Galen Somerville" <galen@community.nospam> wrote in message
news:eAoxI7MWGHA.3492@TK2MSFTNGP05.phx.gbl...
> In my opinion, one of the worst failures of Net (VB2005 Pro) was not
> providing an XOR line draw feature, as in VB6.
>
> A major feature of my app is allowing the user to draw Markers (vertical
> lines) on a trace so they can measure the time difference between markers.
>
> Once they click on a desired location, on a trace, arrow buttons are
> provided so they can move the marker to an exact location. With xor, I
> just redraw the current marker to make it disappear then draw a new marker
> one pixel away. No sweat in VB6.
>
> I have put a screen shot of a typical trace with markers on my web site
> under "Private" then click on "Marker display" "screen shot"
> http://home.surewest.net/galen/index.html
>
> I would appreciate any guidance I can get.
>
> The traces are on a bitmap which is contained in a User Control. I thought
> of drawing the marker on a copy of the bitmap. To move the marker I would
> toss the copy and draw the new marker on a new copy of the original
> bitmap. This, of course, would complicate my User Control.
>
> Also there can be up to four markers displayed. If I move one and toss the
> bitmap copy, I not only have to draw the new marker but I have to redraw
> the other three which didn't move.
>
> As you can see on the screen shot, a marker also shows some text (time
> difference between markers). This means I can't just read in a vertical
> set of pixels and later restore them as the marker is moved.
>
> I could read a vertical rectangle which would be as wide as the worst case
> text size.
>
> Also, as the marker nears the right edge of the screen, the text is placed
> to the left of the marker.
>
> H E L P
>
> GalenS
>
>