> I'm trying to create a program that plots randomly colored pixels on a bitmap
> & then displays the bitmap. When I run the program, I see the pixels being
> plotted down the left side of the form. When it gets to the bottom, the
> "Argument out of range exception" occurs. So, obviously the program starts.
> The Help tells me that the argument isn't within the range of values, but it
> doesn't explain how to fix the problem. So the Help doesn't help! It doesn't
> tell me what the range of values are. What are the range of values? The
> problem is with the "Y" parameter. The debugger tells me that the value
> cannot be negative & must be less than Height.
>
> Here follows the source code:
>
> Private Sub PointillismToolStripMenuItem_Click(ByVal sender As
> System.Object, ByVal e As System.EventArgs) Handles
> PointillismToolStripMenuItem.Click
>
>     Dim objGraphics As Graphics
>     Dim objRandom As System.Random
>     Dim RedColor As Integer
>     Dim GreenColor As Integer
>     Dim BlueColor As Integer
>     Dim Transparency As Integer
>
>     ' Create a Graphics object using the memory bitmap.
>     objGraphics = Graphics.FromImage(objDrawingSurface)
>
>     ' Initialize the Random object.
>     objRandom = New Random(Now.Millisecond)
>
>     Transparency = objRandom.Next(0, 256)
>    
>     Dim Xcount As Integer
>     Dim Ycount As Integer
>
>     For Xcount = 1 To 1280
>       For Ycount = 1 To 964
>         RedColor = objRandom.Next(0, 256)
>         GreenColor = objRandom.Next(0, 256)
>         BlueColor = objRandom.Next(0, 256)
>         objDrawingSurface.SetPixel(Xcount, Ycount, Color.FromArgb(RedColor,
> GreenColor, BlueColor))
>         ' Draw myBitmap to the screen.
>         Me.CreateGraphics.DrawImage(objDrawingSurface, 0, 0)
>       Next Ycount
>     Next Xcount
>
> End Sub
>
> The problem occurs within the "For Ycount" loop at the "objDrawingSurface...".
>
> So, how do I fix the problem. I'm about ready to give up.
>
> Thank you. David

"Göran Andersson" wrote:

> You are simply trying to draw outside the bitmap.
>
> The range for the Y parameter is from 0 to height-1, just like the error
> message tells you.
>
> pcnerd wrote:
> > I'm trying to create a program that plots randomly colored pixels on a bitmap
> > & then displays the bitmap. When I run the program, I see the pixels being
> > plotted down the left side of the form. When it gets to the bottom, the
> > "Argument out of range exception" occurs. So, obviously the program starts.
> > The Help tells me that the argument isn't within the range of values, but it
> > doesn't explain how to fix the problem. So the Help doesn't help! It doesn't
> > tell me what the range of values are. What are the range of values? The
> > problem is with the "Y" parameter. The debugger tells me that the value
> > cannot be negative & must be less than Height.
> >
> > Here follows the source code:
> >
> > Private Sub PointillismToolStripMenuItem_Click(ByVal sender As
> > System.Object, ByVal e As System.EventArgs) Handles
> > PointillismToolStripMenuItem.Click
> >
> >     Dim objGraphics As Graphics
> >     Dim objRandom As System.Random
> >     Dim RedColor As Integer
> >     Dim GreenColor As Integer
> >     Dim BlueColor As Integer
> >     Dim Transparency As Integer
> >
> >     ' Create a Graphics object using the memory bitmap.
> >     objGraphics = Graphics.FromImage(objDrawingSurface)
> >
> >     ' Initialize the Random object.
> >     objRandom = New Random(Now.Millisecond)
> >
> >     Transparency = objRandom.Next(0, 256)
> >    
> >     Dim Xcount As Integer
> >     Dim Ycount As Integer
> >
> >     For Xcount = 1 To 1280
> >       For Ycount = 1 To 964
> >         RedColor = objRandom.Next(0, 256)
> >         GreenColor = objRandom.Next(0, 256)
> >         BlueColor = objRandom.Next(0, 256)
> >         objDrawingSurface.SetPixel(Xcount, Ycount, Color.FromArgb(RedColor,
> > GreenColor, BlueColor))
> >         ' Draw myBitmap to the screen.
> >         Me.CreateGraphics.DrawImage(objDrawingSurface, 0, 0)
> >       Next Ycount
> >     Next Xcount
> >
> > End Sub
> >
> > The problem occurs within the "For Ycount" loop at the "objDrawingSurface...".
> >
> > So, how do I fix the problem. I'm about ready to give up.
> >
> > Thank you. David
>

> I want to be able to display a bitmap that I've
> created one line at a time from the top of the form to the botom. How do I do
> that?
>
> "Göran Andersson" wrote:
>
>> You are simply trying to draw outside the bitmap.
>>
>> The range for the Y parameter is from 0 to height-1, just like the error
>> message tells you.
>>
>> pcnerd wrote:
>>> I'm trying to create a program that plots randomly colored pixels on a bitmap
>>> & then displays the bitmap. When I run the program, I see the pixels being
>>> plotted down the left side of the form. When it gets to the bottom, the
>>> "Argument out of range exception" occurs. So, obviously the program starts.
>>> The Help tells me that the argument isn't within the range of values, but it
>>> doesn't explain how to fix the problem. So the Help doesn't help! It doesn't
>>> tell me what the range of values are. What are the range of values? The
>>> problem is with the "Y" parameter. The debugger tells me that the value
>>> cannot be negative & must be less than Height.
>>>
>>> Here follows the source code:
>>>
>>> Private Sub PointillismToolStripMenuItem_Click(ByVal sender As
>>> System.Object, ByVal e As System.EventArgs) Handles
>>> PointillismToolStripMenuItem.Click
>>>
>>>     Dim objGraphics As Graphics
>>>     Dim objRandom As System.Random
>>>     Dim RedColor As Integer
>>>     Dim GreenColor As Integer
>>>     Dim BlueColor As Integer
>>>     Dim Transparency As Integer
>>>
>>>     ' Create a Graphics object using the memory bitmap.
>>>     objGraphics = Graphics.FromImage(objDrawingSurface)
>>>
>>>     ' Initialize the Random object.
>>>     objRandom = New Random(Now.Millisecond)
>>>
>>>     Transparency = objRandom.Next(0, 256)
>>>    
>>>     Dim Xcount As Integer
>>>     Dim Ycount As Integer
>>>
>>>     For Xcount = 1 To 1280
>>>       For Ycount = 1 To 964
>>>         RedColor = objRandom.Next(0, 256)
>>>         GreenColor = objRandom.Next(0, 256)
>>>         BlueColor = objRandom.Next(0, 256)
>>>         objDrawingSurface.SetPixel(Xcount, Ycount, Color.FromArgb(RedColor,
>>> GreenColor, BlueColor))
>>>         ' Draw myBitmap to the screen.
>>>         Me.CreateGraphics.DrawImage(objDrawingSurface, 0, 0)
>>>       Next Ycount
>>>     Next Xcount
>>>
>>> End Sub
>>>
>>> The problem occurs within the "For Ycount" loop at the "objDrawingSurface...".
>>>
>>> So, how do I fix the problem. I'm about ready to give up.
>>>
>>> Thank you. David

"Göran Andersson" wrote:

> pcnerd wrote:
> > I came up with an alternative way. I originally used nested For-Next loops.
> > The inner loop executes in its entirety before the outside loop. So, the Y
> > coordinate goes from 0 to 964 & then exits the For-Y loop. The next time the
> > Y value is already at its maximum so the error pops up.
>
> No, that's not correct.
>
> If you specify a loop to go from a specific value to another, it will
> always use the same values, even if the loop is inside another loop. The
> loop counter is always initialized at the start of the loop.
>
> > So, I used just one
> > For-Next loop & set the X & Y coordinates in the SetPixel to random values.
> > It works! I have a pretty fast PC, but the pixels take forever to plot. It
> > takes like 10 to 15 seconds just to draw a few thousand pixels.
>
> That's because you are doing quite a lot more than just plotting the
> pixels. You are drawing the entire bitmap to the screen for every pixel
> that you plot.
>
> <question type="rethorical">
>
> What do you think is taking longer in the loop, plotting the pixel or
> drawing the bitmap?
>
> </question>
>
> > The VB6
> > program can draw tens of thousands in a couple of seconds. I tried basically
> > the same program in VB6 & the pixels were drawn very quickly. I guess that
> > the reason that VB.NET is so slow with graphics is because every thing is an
> > object. Is there any way to speed up the process?
> >
> > In a like question. Now that I know how to draw pixels at random, how do I
> > draw them in sequence?
>
> Use a loop. Like you did from the start.
>
> > I want to be able to display a bitmap that I've
> > created one line at a time from the top of the form to the botom. How do I do
> > that?
> >
> > "Göran Andersson" wrote:
> >
> >> You are simply trying to draw outside the bitmap.
> >>
> >> The range for the Y parameter is from 0 to height-1, just like the error
> >> message tells you.
> >>
> >> pcnerd wrote:
> >>> I'm trying to create a program that plots randomly colored pixels on a bitmap
> >>> & then displays the bitmap. When I run the program, I see the pixels being
> >>> plotted down the left side of the form. When it gets to the bottom, the
> >>> "Argument out of range exception" occurs. So, obviously the program starts.
> >>> The Help tells me that the argument isn't within the range of values, but it
> >>> doesn't explain how to fix the problem. So the Help doesn't help! It doesn't
> >>> tell me what the range of values are. What are the range of values? The
> >>> problem is with the "Y" parameter. The debugger tells me that the value
> >>> cannot be negative & must be less than Height.
> >>>
> >>> Here follows the source code:
> >>>
> >>> Private Sub PointillismToolStripMenuItem_Click(ByVal sender As
> >>> System.Object, ByVal e As System.EventArgs) Handles
> >>> PointillismToolStripMenuItem.Click
> >>>
> >>>     Dim objGraphics As Graphics
> >>>     Dim objRandom As System.Random
> >>>     Dim RedColor As Integer
> >>>     Dim GreenColor As Integer
> >>>     Dim BlueColor As Integer
> >>>     Dim Transparency As Integer
> >>>
> >>>     ' Create a Graphics object using the memory bitmap.
> >>>     objGraphics = Graphics.FromImage(objDrawingSurface)
> >>>
> >>>     ' Initialize the Random object.
> >>>     objRandom = New Random(Now.Millisecond)
> >>>
> >>>     Transparency = objRandom.Next(0, 256)
> >>>    
> >>>     Dim Xcount As Integer
> >>>     Dim Ycount As Integer
> >>>
> >>>     For Xcount = 1 To 1280
> >>>       For Ycount = 1 To 964
> >>>         RedColor = objRandom.Next(0, 256)
> >>>         GreenColor = objRandom.Next(0, 256)
> >>>         BlueColor = objRandom.Next(0, 256)
> >>>         objDrawingSurface.SetPixel(Xcount, Ycount, Color.FromArgb(RedColor,
> >>> GreenColor, BlueColor))
> >>>         ' Draw myBitmap to the screen.
> >>>         Me.CreateGraphics.DrawImage(objDrawingSurface, 0, 0)
> >>>       Next Ycount
> >>>     Next Xcount
> >>>
> >>> End Sub
> >>>
> >>> The problem occurs within the "For Ycount" loop at the "objDrawingSurface...".
> >>>
> >>> So, how do I fix the problem. I'm about ready to give up.
> >>>
> >>> Thank you. David
>

> I'm sorry.
>
> "Göran Andersson" wrote:
>
>> pcnerd wrote:
>>> I came up with an alternative way. I originally used nested For-Next loops.
>>> The inner loop executes in its entirety before the outside loop. So, the Y
>>> coordinate goes from 0 to 964 & then exits the For-Y loop. The next time the
>>> Y value is already at its maximum so the error pops up.
>> No, that's not correct.
>>
>> If you specify a loop to go from a specific value to another, it will
>> always use the same values, even if the loop is inside another loop. The
>> loop counter is always initialized at the start of the loop.
>>
>>> So, I used just one
>>> For-Next loop & set the X & Y coordinates in the SetPixel to random values.
>>> It works! I have a pretty fast PC, but the pixels take forever to plot. It
>>> takes like 10 to 15 seconds just to draw a few thousand pixels.
>> That's because you are doing quite a lot more than just plotting the
>> pixels. You are drawing the entire bitmap to the screen for every pixel
>> that you plot.
>>
>> <question type="rethorical">
>>
>> What do you think is taking longer in the loop, plotting the pixel or
>> drawing the bitmap?
>>
>> </question>
>>
>>> The VB6
>>> program can draw tens of thousands in a couple of seconds. I tried basically
>>> the same program in VB6 & the pixels were drawn very quickly. I guess that
>>> the reason that VB.NET is so slow with graphics is because every thing is an
>>> object. Is there any way to speed up the process?
>>>
>>> In a like question. Now that I know how to draw pixels at random, how do I
>>> draw them in sequence?
>> Use a loop. Like you did from the start.
>>
>>> I want to be able to display a bitmap that I've
>>> created one line at a time from the top of the form to the botom. How do I do
>>> that?
>>>
>>> "Göran Andersson" wrote:
>>>
>>>> You are simply trying to draw outside the bitmap.
>>>>
>>>> The range for the Y parameter is from 0 to height-1, just like the error
>>>> message tells you.
>>>>
>>>> pcnerd wrote:
>>>>> I'm trying to create a program that plots randomly colored pixels on a bitmap
>>>>> & then displays the bitmap. When I run the program, I see the pixels being
>>>>> plotted down the left side of the form. When it gets to the bottom, the
>>>>> "Argument out of range exception" occurs. So, obviously the program starts.
>>>>> The Help tells me that the argument isn't within the range of values, but it
>>>>> doesn't explain how to fix the problem. So the Help doesn't help! It doesn't
>>>>> tell me what the range of values are. What are the range of values? The
>>>>> problem is with the "Y" parameter. The debugger tells me that the value
>>>>> cannot be negative & must be less than Height.
>>>>>
>>>>> Here follows the source code:
>>>>>
>>>>> Private Sub PointillismToolStripMenuItem_Click(ByVal sender As
>>>>> System.Object, ByVal e As System.EventArgs) Handles
>>>>> PointillismToolStripMenuItem.Click
>>>>>
>>>>>     Dim objGraphics As Graphics
>>>>>     Dim objRandom As System.Random
>>>>>     Dim RedColor As Integer
>>>>>     Dim GreenColor As Integer
>>>>>     Dim BlueColor As Integer
>>>>>     Dim Transparency As Integer
>>>>>
>>>>>     ' Create a Graphics object using the memory bitmap.
>>>>>     objGraphics = Graphics.FromImage(objDrawingSurface)
>>>>>
>>>>>     ' Initialize the Random object.
>>>>>     objRandom = New Random(Now.Millisecond)
>>>>>
>>>>>     Transparency = objRandom.Next(0, 256)
>>>>>    
>>>>>     Dim Xcount As Integer
>>>>>     Dim Ycount As Integer
>>>>>
>>>>>     For Xcount = 1 To 1280
>>>>>       For Ycount = 1 To 964
>>>>>         RedColor = objRandom.Next(0, 256)
>>>>>         GreenColor = objRandom.Next(0, 256)
>>>>>         BlueColor = objRandom.Next(0, 256)
>>>>>         objDrawingSurface.SetPixel(Xcount, Ycount, Color.FromArgb(RedColor,
>>>>> GreenColor, BlueColor))
>>>>>         ' Draw myBitmap to the screen.
>>>>>         Me.CreateGraphics.DrawImage(objDrawingSurface, 0, 0)
>>>>>       Next Ycount
>>>>>     Next Xcount
>>>>>
>>>>> End Sub
>>>>>
>>>>> The problem occurs within the "For Ycount" loop at the "objDrawingSurface...".
>>>>>
>>>>> So, how do I fix the problem. I'm about ready to give up.
>>>>>
>>>>> Thank you. David