i draw the circle in c# using directx.i like to draw the circle with same dimensions in c# using GDI.It means i like to convert that circle from directx to GDI. Is any body help for me.plz provide the answer for me.how can i do it.Is any algorithm available for that........
And also i give the input for center of the circle is (x,y)in this point format.but in gdi it is pixel format .so how can i convert the directx points to gdi+ pixels
Here is a link from MSDN that introduces Graphics and Drawing in Windows Forms. And it's likely that you will need something similar to:
public Form1()
{
InitializeComponent();
this.Paint += new PaintEventHandler(Form1_Paint);
// This works too
//this.Paint += (_, args) => DrawCircle(args.Graphics);
}
void Form1_Paint(object sender, PaintEventArgs e)
{
DrawCircle(e.Graphics);
}
private void DrawCircle(Graphics g)
{
int x = 0;
int y = 0;
int radius = 50;
// The x,y coordinates here represent the upper left corner
// so if you have the center coordinates (cenX, cenY), you will have to
// substract radius from both cenX and cenY in order to represent the
// upper left corner.
// The width and height represents that of the bounding rectangle of the circle
g.DrawEllipse(Pens.Black, x, y, radius * 2, radius * 2);
// Use this instead if you need a filled circle
//g.FillEllipse(Brushes.Black, x, y, radius * 2, radius * 2);
}
After that you might want to look into double-buffering techniques, a few links :
[SO] How to double buffer .NET controls on a form?
[MSDN] Double Buffered Graphics
[MSDN] Using Double Buffering
Related
I've been trying for hours but can't seem to figure it out. How can I get the bar-graph to sit on the bottom of the picture box without instead of it hanging from the top. Here is a picture of what it looks like so far. I've tried changing the Y position but it just moves the whole graph downwards rather then inverting it.
I want to take the distance walked and display it in a bar graph using the DrawRectangle, DrawLine Method. Here are the two methods I am using to draw the bar graph:
Method to retrieve data from list then display as bar graph in picture box:
private void DrawBarGraph()
{
Graphics canvas = pictureBoxTop.CreateGraphics();
int x = 200;
int y = 0;
foreach (int i in distanceList)
{
int length = SCALE_FACTOR * i;
DrawABar(canvas, x, y, length , Color.Red);
x += BAR_WIDTH + GAP;
}
}
Method to draw bars:
private void DrawABar(Graphics paper, int x, int y, int length, Color colour)
{
//create a brush of specified colour and fill background with this colour
SolidBrush brush = new SolidBrush(colour);
paper.FillRectangle(brush, x, y, BAR_WIDTH, length);
//draw outline in black
paper.DrawRectangle(Pens.Black, x, y, BAR_WIDTH, length);
}
Bar graph drawing with DrawRectangle method.
OP's solution (extracted from question post)
/// <summary>
/// Draw a bar graph in the picture box
/// </summary>
private void DrawBarGraph()
{
Graphics canvas = pictureBoxTop.CreateGraphics();
// Set world transform of graphics object to translate.
canvas.TranslateTransform(1200.0F, 195.0F);
// Then to rotate, prepending rotation matrix.
canvas.RotateTransform(180.0F);
//set row and column length then allocate colors to specific columns
int x = 0;
int y = 0;
foreach (int i in distanceList)
{
int length = SCALE_FACTOR * i;
DrawABar(canvas, x, y,length , Color.Red);
x += BAR_WIDTH + GAP;
}
}
After a couple of google searches and a bit more playing around I came across two methods designed to rotate the images inside of a picture box.
Here is the picture below:
Inverted bar graph using RotateTransfrom and RotateFlip Properties.
This question is asked before but since it doesn't work and my lack of reputation point(I tried to comment at question but I couldn't) I had to ask this question again.
This is the link of the quustion asked before;
How to zoom at a point in picturebox
I used the code which is shown in the link but when I run it the point or shape disappear.
here is my code;
public partial class Form1 : Form
{
private Matrix transform = new Matrix();
private double m_dZoomscale = 1.0;
public static double s_dScrollValue = .1;
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
g.Transform = transform;
Pen mypen = new Pen(Color.Red,5);
Rectangle rect = new Rectangle(10, 10, 30, 30);
e.Graphics.DrawRectangle(mypen, rect);
}
protected override void OnMouseWheel(MouseEventArgs mea)
{
pictureBox1.Focus();
if (pictureBox1.Focused == true && mea.Delta != 0)
{
ZoomScroll(mea.Location, mea.Delta > 0);
}
}
private void ZoomScroll(Point location, bool zoomIn)
{
transform.Translate(-location.X, -location.Y);
if (zoomIn)
transform.Scale((float)s_dScrollValue, (float)s_dScrollValue);
else
transform.Scale((float)-s_dScrollValue, (float)-s_dScrollValue);
transform.Translate(location.X, location.Y);
pictureBox1.Invalidate();
}
The answer you are referencing cannot possibly work. I have no idea why it was accepted, nor up-voted. Except that at some time in the past, I apparently up-voted it as well. I don't know what I was thinking.
Anyway, that code has some problems:
It uses the mouse coordinates passed in directly, rather than converting them to the coordinate system for the PictureBox control. The coordinates passed to the OnMouseWheel() method are relative to the Form itself, so only if the PictureBox top-left coincides with the Form's upper-left corner would that work.
More problematically, the code is completely misusing the Matrix.Scale() method, passing a value that seems intended to be a delta for the scale, when in fact the Scale() method accepts a factor for the scale. This has two implications:
Passing a negative value is wrong, because negative values flip the coordinate system, rather than reducing the scale, and
Passing an increment value is wrong, because the value passed will be multiplied with the current scaling to get the new scaling.
Also problematic is that the code applies the matrix transformations in the wrong order, because the default order is "prepend", not "append" (I find the latter more natural to work with, but I assume there's some reason known to those who specialize in matrix math that explains why the default is the former).
There is also the relatively minor issue that, even ignoring the above, allowing the user to adjust the scale factor arbitrarily will eventually lead to an out-of-range value. It would be better for the code to limit the scale to something reasonable.
Here is a version of your code, modified so that it addresses all of these issues:
private Matrix transform = new Matrix();
private float m_dZoomscale = 1.0f;
public const float s_dScrollValue = 0.1f;
public Form1()
{
InitializeComponent();
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
g.Transform = transform;
Pen mypen = new Pen(Color.Red, 5);
Rectangle rect = new Rectangle(10, 10, 30, 30);
e.Graphics.DrawRectangle(mypen, rect);
}
protected override void OnMouseWheel(MouseEventArgs mea)
{
pictureBox1.Focus();
if (pictureBox1.Focused == true && mea.Delta != 0)
{
// Map the Form-centric mouse location to the PictureBox client coordinate system
Point pictureBoxPoint = pictureBox1.PointToClient(this.PointToScreen(mea.Location));
ZoomScroll(pictureBoxPoint, mea.Delta > 0);
}
}
private void ZoomScroll(Point location, bool zoomIn)
{
// Figure out what the new scale will be. Ensure the scale factor remains between
// 1% and 1000%
float newScale = Math.Min(Math.Max(m_dZoomscale + (zoomIn ? s_dScrollValue : -s_dScrollValue), 0.1f), 10);
if (newScale != m_dZoomscale)
{
float adjust = newScale / m_dZoomscale;
m_dZoomscale = newScale;
// Translate mouse point to origin
transform.Translate(-location.X, -location.Y, MatrixOrder.Append);
// Scale view
transform.Scale(adjust, adjust, MatrixOrder.Append);
// Translate origin back to original mouse point.
transform.Translate(location.X, location.Y, MatrixOrder.Append);
pictureBox1.Invalidate();
}
}
With this code, you will find that no matter where you place the mouse before adjusting the mouse wheel, the rendered image will scale while keeping the point under the mouse fixed in place.
Note:
I took a look at some of the similar questions on Stack Overflow, and there are a few that might also be useful to you. Some of the answers overcomplicate things, in my opinion, but all should work. See:
Zoom To Point Not Working As Expected
Zoom in on a fixed point using matrices
Zooming graphics without scrolling
I have a facial recognition library working that gives me an array of rectangle. Right now I'm using this way to draw the rectangle.
foreach (Rectangle box in boxes)
{
for (int x = box.X; x <= box.X + box.Width; x++)
{
for (int y = box.Y; y <= box.Y + box.Height; y++)
{
outputbmp.SetPixel(x, y, Color.FromKnownColor(KnownColor.Red));
}
}
}
I'm looking for something as simple as:
Ellipse ellipse = new Ellipse(box); //cast rect to ellipse
outputbmp.DrawEllipse(ellipse);
which will look something more like:
where the outline of the ellipse touching the rectangle corners.
Based on the approach I used above, it is easy to draw a rectangle but for ellipse, it would require me to know all the points in the ellipse. Just wonder if there's anything to make my life easier.
Don't try to draw directly to the bitmap, there is a higher level object you can create, called a Graphics that gives you all kinds of wonderful drawing tools. It will also be significantly faster than drawing pixel by pixel.
You can create a Graphics for a given Bitmap by calling Graphics.FromImage and passing in the bitmap. You must remember ti call Dispose on the Graphics though, or it will leak resources.
Once you have a Graphics instance for your bitmap you can call DrawEllipse and pass in the bounds exactly as you expect.
From MSDN:
private void DrawEllipseInt(Graphics g)
{
// Create pen.
Pen blackPen = new Pen(Color.Black, 3);
// Create location and size of ellipse.
int x = 0;
int y = 0;
int width = 200;
int height = 100;
// Draw ellipse to screen.
g.DrawEllipse(blackPen, x, y, width, height);
}
I'm trying to draw some polygons and lines usinng e.Graphics.DrawPolygon (or DrawLine). But I have a little problem specifying the coordinates where to draw. I am drawing onto a PictureBox using its Paint event. The elements draw correctly relatively to each other (creating the required final picture), but seem always to draw in the upper-left corner of the PictureBox. When creating the points to draw, when I just try to multiply the coordinates, it draws it at the same place but bigger (size is multiplied, instead of location coordinates).
Here is my code:
//some for loop
{
//getting the coordinates
Point toAdd = new Point((int)xCoord, (int)yCoord); // creating the point from originaly a double, here i tried to multiply..
tmpPoints.Add(toAdd); // tmpPoints is a List<Point>
}
points.Add(tmpPoints.ToArray()); //List<Point[]>
drawBuffer = points; //saving to a public List<Point[]>
points.Clear();
this.Invalidate();
here part of the pictureBox1_Paint method:
for (int i = 0; i < drawBuffer.Count; i++)
{
//some other stuff like deciding which color to use, not very important
Brush br = new SolidBrush(polyColor);
e.Graphics.FillPolygon(br, drawBuffer[i]);
brush.Dispose();
}
I have checked using breakpoint, the coordiinates are the same ratio (what was 100 pixels wide is still 100 pixels wide), they are at coordinates like x 3000 and y 1500, but it just draws itself in the upper-left corner. When i multiply the coordinates 3 times (see the code for the place where i multiplied), it draws at the same place but 3 times bigger (doesn't make sense after checking the coords...)
So, my question is - how do I set the location correctly, or is there any other way to do this?
Like this (I know, this is nonsense, just an example)
foreach(Polygon poly in e.Graphics)
{
poly.Location = new Point(poly.Location.X * 2, poly.Location.Y * 2);
}
When you multiply the coordinates of the points, they're scaled around the point (0, 0), the top-left corner of the canvas:
In order to scale it around its center (and I suppose you expected it to work this way), you need to calculate some kind of center of the polygon. For simplicity, it can be even an arithmetic mean of the coordinates, on X and Y axes respectively. If you already have the coordinates of the center, translate the coordinates of every point by a reversed vector made from the center coordinates (this is how it would look like if you drew it after this operation - the polygon's center is in the center of the coordinate system):
Now, do your scaling:
and move it back by the vector of polygon's center coordinates:
when you multiply
poly.Location = new Point(poly.Location.X * 2, poly.Location.Y * 2);
you are doing a stretch operation when you add
poly.Location = new Point(poly.Location.X + 50, poly.Location.Y +50); you are doing a translation operation.
If you want to shift everything without modifying the stored coords then just translate the graphics before drawing:
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.TranslateTransform(100, 100); // shift the origin somehow
// ... draw the polygons as before ...
}
using Cairo;
I have drawn a rectangle inside a bigger rectangle witch is inside a drawing area.
I have managed to attach a event to the Drawing area witch is a object I have extended from it
this.AddEvents ((int) EventMask.ButtonPressMask);
this.ButtonPressEvent += delegate(object o, ButtonPressEventArgs args) {
hasInterface(args.Event.X, args.Event.Y);
Console.WriteLine("Button Pressed " + args.Event.X + ", " + args.Event.Y);
};
I'm dynamically drawing the squares using:
cr.Translate(width/2, height/2);
cr.Rectangle((pX + (i * tmp)) , pY, boxsize, boxsize);
private void recordPosition(double x, double y)
{
x = x*2;
y = y*2;
boxCoordinates.Add( new double[,]
{
{x, y}
}
); // store coords
}
List<double,double> boxCoordinates
So for the inside of the drawing area the square is drawn at x=0, y=0 from the "outside" point of view it's in x=90, y=45; the width = 180 , height = 100
I was using translate (since half of this is copied ) of the size/2 so this means that the drawing area was doing a resize of the square, to solve this issue I was saving the position's multiplying it by 2, but this is not working has I'm getting "hits" outside of the rectangle drawn.
What is the best way to do this? I mean to translate the X Y positions from the window to the drawing area, I saw this was possible in other languages but not sure how to do it in C# and the drawing area from mono.
Thanks for any help.
I've done this a few times in C w SDL and C# with Cairo, basically, you want to be able to convert the bounding box of each of your rectangles to and from the coordinates you are using for rendering on the cairo canvas.
For each of your rectangles, you'll have the location you of your rectangles in thier own world. I like to call these the "world coordinates" and their "screen coordinates" (which map to where your mouse will be).
You can store the world coordinates of each box and then translate them to screen ones for each frame you render.
public class Shape {
public Point WorldLoc { get; set; }
}
You would do all your physics (if you have any) on the WorldLoc values. When you come to render, You want to be able to convert your WorldLoc to ScreenLoc.
public class Scene {
public double Zoom;
public Point Offset;
public Point WorldToScreen( Point world ){
var p = new Point();
p.x = (world.x - Offset.x) * Zoom;
p.y = (world.y - Offset.y) * Zoom;
return p;
}
}
Each time you render somthing in this Scene, you'll use WorldToScreen() to get the screen coordinates. You can then use the same thing to work out if your mouse is in the screen box of a world box.