How to draw a one-pixel line??
in [CSharp]
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From: Family Tree Mike on 4 Nov 2009 20:40 Loren Pechtel wrote: > On Wed, 04 Nov 2009 12:30:56 -0800, Peter Duniho > <no.peted.spam(a)no.nwlink.spam.com> wrote: > >> Loren Pechtel wrote: >>> I agree it sounds exactly like fractional coordinates. How do you >>> draw on fractional coordinates with integer variables, though? [...] >> By drawing in an environment where coordinates given as integers are >> scaling somehow. >> >> I posted a code example that shows that in general, the problem you >> describe does not occur. Either your own code does something different, >> or you are simply not observing the results correctly (i.e. you think >> there's a problem when there's not). >> >> In the latter case, obviously there's nothing to fix. In the former >> case, until you post a concise-but-complete code example that reliably >> demonstrates the issue, there's no way to tell you how to fix your code. > > I managed to reproduce it very easily: > > A form containing a panel that contains a picture box. Drawing: > > Bitmap Image = new Bitmap(Box.ClientSize.Width > ,Box.ClientSize.Height); > Pen Ink = new Pen(Color.Black, -1); > using (Graphics Paper = Graphics.FromImage(Image)) > { > Paper.Clear(Color.LightGray); > for (int x = 2; x < Image.Width / 2; x += 2) > Paper.DrawLine(Ink, x, 0, x, Image.Height - 1); > for (int y = 2; y < Image.Height; y += 2) > Paper.DrawLine(Ink, Image.Width / 2, y, Image.Width - > 1, y); > } > Box.Image = Image; > > Obviously the panel in this case is useless but I simply copied the > layout from the main code--in the main code there are some controls > off to the side and I use the panel to make the picture box take up > the whole form. > > This code *SHOULD* draw one half of the screen with vertical lines and > one half with horizontal. I'm getting a gray mass on the left and the > expected behavior on the right. For what it is worth, I see what you say it *SHOULD* draw when I execute your routine. -- Mike
From: Loren Pechtel on 4 Nov 2009 21:33 On Wed, 04 Nov 2009 20:40:56 -0500, Family Tree Mike <FamilyTreeMike(a)ThisOldHouse.com> wrote: >Loren Pechtel wrote: >> On Wed, 04 Nov 2009 12:30:56 -0800, Peter Duniho >> <no.peted.spam(a)no.nwlink.spam.com> wrote: >> >>> Loren Pechtel wrote: >>>> I agree it sounds exactly like fractional coordinates. How do you >>>> draw on fractional coordinates with integer variables, though? [...] >>> By drawing in an environment where coordinates given as integers are >>> scaling somehow. >>> >>> I posted a code example that shows that in general, the problem you >>> describe does not occur. Either your own code does something different, >>> or you are simply not observing the results correctly (i.e. you think >>> there's a problem when there's not). >>> >>> In the latter case, obviously there's nothing to fix. In the former >>> case, until you post a concise-but-complete code example that reliably >>> demonstrates the issue, there's no way to tell you how to fix your code. >> >> I managed to reproduce it very easily: >> >> A form containing a panel that contains a picture box. Drawing: >> >> Bitmap Image = new Bitmap(Box.ClientSize.Width >> ,Box.ClientSize.Height); >> Pen Ink = new Pen(Color.Black, -1); >> using (Graphics Paper = Graphics.FromImage(Image)) >> { >> Paper.Clear(Color.LightGray); >> for (int x = 2; x < Image.Width / 2; x += 2) >> Paper.DrawLine(Ink, x, 0, x, Image.Height - 1); >> for (int y = 2; y < Image.Height; y += 2) >> Paper.DrawLine(Ink, Image.Width / 2, y, Image.Width - >> 1, y); >> } >> Box.Image = Image; >> >> Obviously the panel in this case is useless but I simply copied the >> layout from the main code--in the main code there are some controls >> off to the side and I use the panel to make the picture box take up >> the whole form. >> >> This code *SHOULD* draw one half of the screen with vertical lines and >> one half with horizontal. I'm getting a gray mass on the left and the >> expected behavior on the right. > >For what it is worth, I see what you say it *SHOULD* draw when I execute >your routine. What in the world is the difference then? How do I get it to draw what you're seeing?
From: Family Tree Mike on 4 Nov 2009 21:55 Loren Pechtel wrote: > On Wed, 04 Nov 2009 20:40:56 -0500, Family Tree Mike > <FamilyTreeMike(a)ThisOldHouse.com> wrote: > >> Loren Pechtel wrote: >>> On Wed, 04 Nov 2009 12:30:56 -0800, Peter Duniho >>> <no.peted.spam(a)no.nwlink.spam.com> wrote: >>> <snip> >>> >>> This code *SHOULD* draw one half of the screen with vertical lines and >>> one half with horizontal. I'm getting a gray mass on the left and the >>> expected behavior on the right. >> For what it is worth, I see what you say it *SHOULD* draw when I execute >> your routine. > > What in the world is the difference then? How do I get it to draw > what you're seeing? I suspect screen settings. When I set my display settings really poorly, then I see what you observe. My normal settings are 1680x1050 32 bit color. -- Mike
From: Peter Duniho on 4 Nov 2009 23:04 Loren Pechtel wrote: > What in the world is the difference then? How do I get it to draw > what you're seeing? You've yet to establish it's _not_ drawing what Mike is seeing. Visual inspection isn't good enough. Just because you've drawn a bitmap a certain way, that's no guarantee it will be presented on the screen that way. Pete
From: Peter Duniho on 4 Nov 2009 23:06
Loren Pechtel wrote: > There should be no scaling in my case [...] So you say. But until you post a concise-but-complete code example, it's not possible to know for sure there's not. If I had a nickel for every time someone asked a question, 100% certain that their description of the situation was accurate, only to find it out wasn't... And even if we establish there's no scaling in the _drawing_ of the bitmap, there's still some possibility you've got some non-standard system configuration that is meddling with the display on-screen. Pete |