dev-cpp-users

[Dev-C++] Drawing lines

[<Dx 8a> <vin...@ed...>]

In DirectX's DirectDraw, how do I draw a straight line from Point A having coordinates (x1,y1) to point B with coordinates (x2,y2). is there a specific function for this operation?

Thanks

__________________________________
www.edsamail.com

[Dev-C++] Drawing lines

[Christiaan S. <ck...@ia...>]

How do you put a pixel on the screen?

Re: [Dev-C++] Drawing lines

[Maan M. H. <mm...@pl...>]

You need a graphics library.  And the last time I checked this e-mail list
is not concerned with graphics.  This is the Dev-C++ list.
Maan
----- Original Message -----
From: Christiaan Scholtz
To: dev...@li...
Sent: Wednesday, October 31, 2001 2:09 PM
Subject: [Dev-C++] Drawing lines


How do you put a pixel on the screen?

Re: [Dev-C++] Drawing lines

[Jason H. <jas...@bt...>]

Because direct draw deals with the graphics memory at such a low level =
it really depends upon what display mode you are in. In 8bpp (bits per =
pixel) there is one byte per pixel. 2 for 16bpp, 3 for 24 bpp, and 4 for =
32bpp. Using that information you need to figure out the memory address =
of the particular pixel you want to draw to, which in turn depends upon =
the width and height of the window or screen you are drawing too. The =
basic formula is:

graphics_mem + x*bytespp + y*width

where graphics_mem is a byte pointer (unsigned char) to the first =
location in the memory for the graphics area, bytespp is bytes per pixel =
(1, 2, 3, or 4), and width is the number of bytes to one horizontal line =
of the display (specifically the pitch). x and y are the cooridinates of =
the pixel you want to draw to. i.e.

graphics_mem[x*bytespp + y*pitch] =3D colour_value;

I have been learning all this from Windows Game Programming for Dummies, =
which is getting old now, but is a good book to learn about Direct Draw =
from (IMO). If all you need is basic graphics capabilities in a window =
then you should look into the Windows GDI or alternativly if you are =
familiar with the BGI graphics interface then there is a version =
available for use with Dev-C++ (MinGW), goto =
http://www.cs.colorado.edu/~main/bgi/ for more information.

If you want any more info I'll try to help, Jason.
  ----- Original Message -----=20
  From: Christiaan Scholtz=20
  To: dev...@li...=20
  Sent: Wednesday, October 31, 2001 8:09 PM
  Subject: [Dev-C++] Drawing lines


  How do you put a pixel on the screen?

[Dev-C++] Drawing lines

[Christiaan S. <ck...@ia...>]

Asshole.

-----Original Message-----
From: Maan M. Hamze <mm...@pl...>
To: dev...@li... =
<dev...@li...>
Date: Wednesday, October 31, 2001 11:02 PM
Subject: Re: [Dev-C++] Drawing lines


>You need a graphics library.  And the last time I checked this e-mail =
list
>is not concerned with graphics.  This is the Dev-C++ list.
>Maan
>----- Original Message -----
>From: Christiaan Scholtz
>To: dev...@li...
>Sent: Wednesday, October 31, 2001 2:09 PM
>Subject: [Dev-C++] Drawing lines
>
>
>How do you put a pixel on the screen?
>
>
>_______________________________________________
>Dev-cpp-users mailing list
>Dev...@li...
>https://lists.sourceforge.net/lists/listinfo/dev-cpp-users

[Dev-C++] Drawing lines

[Christiaan S. <ck...@ia...>]

But how do the graphics libraries put a pixel on the screen?  There has =
to be a way! I dont want to use a library

Re: [Dev-C++] Drawing lines

[Kevin W. <ke...@me...>]

Hello everyone,

I have copied the following from the Windows API help files. Does it help?

-----------------------------------------

The SetPixel function sets the pixel at the specified coordinates to the
specified color.

COLORREF SetPixel(

    HDC hdc, // handle of device context
    int X, // x-coordinate of pixel
    int Y, // y-coordinate of pixel
    COLORREF crColor  // pixel color
   );


Parameters

hdc

Identifies the device context.

X

Specifies the x-coordinate, in logical units, of the point to be set.

Y

Specifies the y-coordinate, in logical units, of the point to be set.

crColor

Specifies the color to be used to paint the point.

Return Values

If the function succeeds, the return value is the RGB value that the
function sets the pixel to. This value may differ from the color specified
by crColor; that happens when an exact match for the specified color cannot
be found.
If the function fails, the return value is -1. To get extended error
information, call GetLastError.

Remarks

The function fails if the pixel coordinates lie outside of the current
clipping region.
Not all devices support the SetPixel function. For more information, see
GetDeviceCaps.

----------------------------------------------------------------------------
-------------

Regards,
        Kevin.



----- Original Message -----
From: Christiaan Scholtz <ck...@ia...>
To: <dev...@li...>
Sent: Saturday, November 03, 2001 7:06 PM
Subject: [Dev-C++] Drawing lines



But how do the graphics libraries put a pixel on the screen?  There has to
be a way! I dont want to use a library

RE: [Dev-C++] Drawing lines

[??? <ch...@hi...>]

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Re: [Dev-C++] Drawing lines

[Jason H. <jas...@bt...>]

You can either use the Windows GDI and get a device context etc..., which
isn't recomended if you want speed, or you can write your own algorithm to
do it. You might want to look up something like the Bresenhams algorithm
which does that.

If you want more information I can dig out a copy of Bresenhams I developed
in college?

Jason.


----- Original Message -----
From: "<Dx 8a>" <vin...@ed...>
To: "Dev-C++ mailing list" <dev...@li...>
Sent: Wednesday, October 31, 2001 5:02 AM
Subject: [Dev-C++] Drawing lines


> In DirectX's DirectDraw, how do I draw a straight line from Point A having
coordinates (x1,y1) to point B with coordinates (x2,y2). is there a specific
function for this operation?
>
> Thanks
>
> __________________________________
> www.edsamail.com
>
> _______________________________________________
> Dev-cpp-users mailing list
> Dev...@li...
> https://lists.sourceforge.net/lists/listinfo/dev-cpp-users