Graphics

Help calculating a perpendicular line end point.

4-Jul-14 5:53

pvpeng wrote:
was displayed to be an error.

What error; please do not expect people to guess what messages you are seeing. I cannot find a description for either a Vertex function, or class constructor; is this something you have created yourself?

Re: Bezier Curve issue

Bernhard Hiller13-Jul-14 21:58

Bernhard Hiller

13-Jul-14 21:58

Didn't you understand the answer to your previous question http://www.codeproject.com/Messages/4850994/How-to-write-an-element-address-of-array-in-Csharp.aspx[^]?
You must use the unsafe keyword and use its respective compiler option.

Austin_Cpp28-Jun-14 10:58

Re: Help calculating a perpendicular line end point.

28-Jun-14 10:58

I am working in C++. I am trying to draw a perpendicular hash mark from the start of a sloped line. My code below draws a perpendicular line but when the slope of the original line changes the hash mark appears to change length. When the line is close to horizontal the hash mark looks longest and shortest when the line is close to vertical. I believe the problem is the fixed value for HashLength. Can you show a better way to calculate the end of the perpendicular line(px2,py2) so my hash mark always looks the same size.

//(x1,y1)(x2,y2) //original Line
//(x1,y1)(px1,px2) //Perpendicular Line

Orig_Line_Slope = (y1-y2)/(x1-x2);
Recipical_Slope = ((1.0 / Orig_Line_Slope)*-1);

HashLength = 10.0;

px2 = (x1+HashLength);
py2 = (y1+(Orig_Line_Slope*HashLength));

MoveToEx(hdc, x1, y1, NULL);
LineTo(hdc, px2, py2 );

Yang Kok Wah29-Jun-14 0:33

Yang Kok Wah

29-Jun-14 0:33

//Denote change in x =dx
//Denote change in y =dy
float dx=0.0;
float dy=0.0;

//Then dx^2 + dy^2 = HashLength ^2 ..eq 1

//We can express dy in terms of dy because

// dy/dx= Recipical_Slope
// simplifying..
// dy=Recipical_Slope*dx

//Replacing dy in eq 1, we have
//dx^2 + (Recipical_Slope *dx)^2= HashLength^2
//simplifying..
dx=sqrt(HashLength^2/(1+Recipical_Slope^2));
dy=Recipical_Slope * dx;

px2=x1+dx;
py2=y1+dy;

Re: Help calculating a perpendicular line end point.

Austin_Cpp1-Jul-14 18:41

How to write glutSwapBuffers() in SharpGL format?

1-Jul-14 18:41

To Yang Kok Wah

I tested your solution and it works very well.

Thank You

pvpeng27-Jun-14 11:05

pvpeng

27-Jun-14 11:05

Dear All,

I am a starter in OpenGL and SharpGL. I am using C# and SharpGL. However, I do not know how to write glutSwapBuffers() in OpenGL to SharpGL format.

Thanks in advance.

SharpGL: how to add a solid object to a scene

Member 1075894613-Jun-14 10:31

Member 10758946

13-Jun-14 10:31

I am using SharpGL to add a solid object to a scene by clicking a button.

private void InitElements(Scene scene)
{
var objectRoot = new SharpGL.SceneGraph.Primitives.Folder() { Name = "Root" };
scene.SceneContainer.AddChild(objectRoot);
// This implements free rotation(with translation and rotation).
var camera = GetCamera();
float cmX = camera.Position.X; float cmY = camera.Position.Y; float cmZ = camera.Position.Z;
float tgX = camera.Target.X; float tgY = camera.Target.Y; float tgZ = camera.Target.Z;
float upX = camera.UpVector.X; float upY = camera.UpVector.Y; float upZ = camera.UpVector.Z;
objectArcBallEffect = new ArcBallEffect(cmX, cmY, cmZ, tgX, tgY, tgZ, upX, upY, upZ);
objectRoot.AddEffect(objectArcBallEffect);
var axisRoot = new SharpGL.SceneGraph.Primitives.Folder() { Name = "axis root" };
scene.SceneContainer.AddChild(axisRoot);
axisArcBallEffect = new ArcBallEffect(cmX, cmY, cmZ, tgX, tgY, tgZ, upX, upY, upZ);
axisRoot.AddEffect(axisArcBallEffect);
InitLight(objectRoot);
InitAxis(objectRoot);
InitAxis(axisRoot);
InitFrameElement(6, 24, 7, objectRoot);
}

After I initiate the solid elements in scene, I would like to add a solid object to that scene by clicking a button. I successfully add it in scene. But I cannot drag and rotate it with the initial elements in the scene. It means I didn't successfully add it to the same scene. Thanks in advance.

private void btnAddEllement_Click(object sender, EventArgs e)
{
var objectRoot = new SharpGL.SceneGraph.Primitives.Folder() { Name = "Root" };
var scene = this.sceneControl1.Scene;
addCylinder(objectRoot, 50, 30, 100, 5);
scene.SceneContainer.AddChild(objectRoot);
}

Re: SharpGL: how to add a solid object to a scene

Richard MacCutchan13-Jun-14 21:40

How to make a font height equal to "tmHeight"?

13-Jun-14 21:40

Please do not repost, see http://www.codeproject.com/Messages/1278604/How-to-get-an-answer-to-your-question.aspx[^], especially point 1.

transoft12-Jun-14 9:02

transoft

12-Jun-14 9:02

Hi,

When I printed a text on screen, I saw the text height equal to "tmHeight- tmInternalLeading".

For example: I printed a text size "8" on screen, I got the actual text height "tmHeight - tmInternalLeading" which is less than "8".

I printed a letter of "H" which height is less than "8", when I used "Arial" true type font of size "8".

Is there a way to make a actual text height (on screen) (ascent) equal to "8"?

Best,

-- modified 12-Jun-14 15:38pm.

Eddy Vluggen12-Jun-14 10:25

Eddy Vluggen

12-Jun-14 10:25

8 points, 8 pixel, 8em? And where?

transoft wrote:
Is there a way to make a actual text height (on screen) (ascent) equal to "8"?

Yes, by setting the font-size. Do keep in mind that different characters have different heights', unless you're using a monospace font like courier.

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

transoft12-Jun-14 11:00

transoft

12-Jun-14 11:00

Thanks for reply.

Maybe I did not make clear.

I set font size to be 8 unit which should be printed on screen to be (suppose) 100. But I got 90 (letter height) which equals to ascent.

It looks like font size is defined to be equal to "ascent + InternalLeading".

My question is: Is there a way to let (letter height) to be "ascent + InternalLeading".

Eddy Vluggen13-Jun-14 2:59

Eddy Vluggen

13-Jun-14 2:59

transoft wrote:
Maybe I did not make clear.

True. Which "unit"? A pixel can be a unit, a centimeter can be one.

Printed on screen? On a form as a label? Drawed as a bitmap?

transoft wrote:
It looks like font size is defined to be equal to "ascent + InternalLeading".

Where did you get that information? The font size is usually set by specifying the size property, as shown here[^]. Can you post some code that explains what you're doing?

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

Needed: Printing Tutorial for GDI+ screen to Single Page

jinzai17-Jul-14 14:01

jinzai

17-Jul-14 14:01

The information -- is correct. There is internal leading (rhymes with sledding) and external leading. They are there to pad the character within its space and to provide space between lines for things like ascenders and descenders, which exceed the character's space.

Austin_Cpp29-May-14 11:23

Re: Needed: Printing Tutorial for GDI+ screen to Single Page

29-May-14 11:23

I am using C++ and GDI+. I am drawing 2D diagrams. I am using the standard lines, ellipse, rotation transformations and Fonts. I need to scale the print so the screen image fills a single page. I need to avoid pixilation, the print should retain the curved lines and curves in the font. The GDI+ print tutorials I am finding are very basic. Can someone point me to a GDI+ printing tutorial that shows this type of scaled printing.

Thanks
Larry

Richard MacCutchan29-May-14 22:17

Re: Needed: Printing Tutorial for GDI+ screen to Single Page

29-May-14 22:17

If you want tutorials then Google should be your first port of call.[^]. If you have specific technical questions then post here.

Austin_Cpp29-May-14 23:33

Re: Needed: Printing Tutorial for GDI+ screen to Single Page

29-May-14 23:33

I have been surprised how difficult it is to print a GDI+ screen as a rescaled fit-to-page. I will go back to google but I have not yet found any c++ code to do this.

Richard MacCutchan30-May-14 21:54