Drawing a big image to real coordinates - C# Discussion Boards

Tracing Invalidate calls (Windows Forms)

Jon Hulatt31-Aug-08 22:58

31-Aug-08 22:58

I'm trying to do some performance enhancements to my project, and, I've discovered that frequently my animation (custom) control is getting painted twice for each distinct frame.

I've traced all calls that I make to Invalidate(), but it seems that something else must be invalidating my control - for every Invalidate call that I make, there are always two calls to OnPaint.

Problem is, Control.Invalidate is not marked virtual, so I cannot trap all calls to base Invalidates, which I suspect is what is causing the seemingly unneccessary Invalidates.

Anyone know of a diagnostic technique that will allow me to establish why my control gets painted, for each call?

using System.Beer;

Re: Tracing Invalidate calls (Windows Forms)

Frank Horn31-Aug-08 23:58

Frank Horn

31-Aug-08 23:58

Can't you trap the calls from the overriden OnPaint() method? Or by overriding OnInvalidated()?

Re: Tracing Invalidate calls (Windows Forms)

leppie1-Sep-08 2:11

leppie

1-Sep-08 2:11

OnInvalidate()

xacc.ide - now with TabsToSpaces support
IronScheme - 1.0 alpha 4a out now (29 May 2008)

Re: Tracing Invalidate calls (Windows Forms)

Jon Hulatt1-Sep-08 2:15

Jon Hulatt

1-Sep-08 2:15

Thanks both, I'd not seen that event before.

This has shed a bit more light on the matter: my control is only getting invalidated once. However, OnPaint is called twice - any idea why?

using System.Beer;

How do I draw a single color transparently?

Megidolaon31-Aug-08 22:47

Megidolaon

31-Aug-08 22:47

I want to draw an image over a background but not the whole image but only the actual content.
I want to specify a color of the foreground image which is transparent and won't be drawn onto the background.

I thought of using a ColorMatrix but I don't really know how I'd do it with this class.

I already used the class to change the alpha value for a whole image, but not for a single color of an image.

How do you use the ColorMatrix to draw a single color transparently?
Or is another approach better?

Thanks in advance.

Re: How do I draw a single color transparently?

oobimoo31-Aug-08 23:29

oobimoo

31-Aug-08 23:29

How to: Draw Images with Transparency[^]

Re: How do I draw a single color transparently?

Megidolaon1-Sep-08 22:56

Megidolaon

1-Sep-08 22:56

Thanks, that works great!

Drawing a big image to real coordinates

ianhunt0131-Aug-08 22:39

ianhunt01

31-Aug-08 22:39

Hi,

I have got a big topographical jpg file that I want to display in a form on a picturebox in its real coordinates that ranges X from 50 000 to 75 000 and Y from 2 800 000 to 2 825 000. this will make it very easy for me to get the mouse coords in real coords as the user invokes the Mousedown event. It will also make it easier for me to draw real features in its real coordinates.

I have got the code:

Image image = Image.FromFile(@"C:\Images\2529DA.jpg");
Pen myPen = new Pen(Color.Black);         
Graphics formGraphics = this.picGrid.CreateGraphics();
formGraphics.Clear(picGrid.BackColor);

formGraphics.DrawImage(image, 0, 0, 1000, 1000);

This shows the topomap nicely on the screen but with the local picturebox coords from 0 to 1000. If I change the code to

formGraphics.DrawImage(image, 50000, 2800000, 25000, 25000);

This previous code then puts the map WAY offscreen to the south-east !

I tried fiddling with the following code but no luck.

formGraphics.DrawImageUnscaled(image,0, 0);
formGraphics.DrawImageUnscaledAndClipped(image, rect1);

please help !

cheers

Ian

Re: Drawing a big image to real coordinates

oobimoo1-Sep-08 0:18

oobimoo

1-Sep-08 0:18

You want to fit a 25000x25000 bitmap in a 1000x1000 bitmap without losing precision? WTF | :WTF:

Re: Drawing a big image to real coordinates

ianhunt011-Sep-08 1:03

ianhunt01

1-Sep-08 1:03

Yes, (I mean yes, I want to loose the precision in order to know where he is) I need to get the user to select an area he wants to zoom into with the mouse. I want to get the e.X and e.Y of the beginning and end of his zoom and redraw the image meaning i have to move and scale the image with this new info.

I checked later and saw that the image has a resolution of 6500 x 6500 although it covers and area of 25 kilometers by 25 kilometers.

Does this help ?

Ian

Re: Drawing a big image to real coordinates

oobimoo1-Sep-08 8:19

oobimoo

1-Sep-08 8:19

Use the following class

using System;
using System.Drawing;
using System.Drawing.Drawing2D;

namespace some_namespace
{
    class Transformation
    {
        // world: the real world your bitmap represents
        // bitmap: your (unscaled) bitmap
        // screen: the portion of the screen that you display the image (a picture box maybe)

        Matrix matrix_world;       // bitmap to world
        Matrix inv_matrix_world;   // world to bitmap
        Matrix matrix_bitmap;      // screen to bitmap
        Matrix inv_matrix_bitmap;  // bitmap to screen

        Size bitmap_size;
        Size screen_size;


        public Transformation(PointF worldOrigin, SizeF worldSize, 
            Size bitmapSize, Size screenSize)
        {
            matrix_world = new Matrix();
            matrix_bitmap = new Matrix();
            bitmap_size = bitmapSize;
            screen_size = screenSize;

            // if you want the native y-points up coord system for the world, uncomment '-' and
            // '+ worldSize.Height' below
            matrix_world.Scale(worldSize.Width / (float)bitmap_size.Width, 
               /* - */ worldSize.Height / (float)bitmap_size.Height);                 
            matrix_world.Translate(worldOrigin.X, 
                worldOrigin.Y /* + worldSize.Height */, MatrixOrder.Append);
            inv_matrix_world = matrix_world.Clone();
            inv_matrix_world.Invert();
            Reset();
        }
 
        // Reset transformation to the 'screen portion displays entire bitmap'
        public void Reset()
        {
            matrix_bitmap.Reset();
            matrix_bitmap.Scale((float)bitmap_size.Width / (float)screen_size.Width, 
                (float)bitmap_size.Height / (float)screen_size.Height);
            inv_matrix_bitmap = matrix_bitmap.Clone();
            inv_matrix_bitmap.Invert();
        }

        // transform to 'screen portion displays the rectangular portion of the bitmap 
        // defined by the displayOrigin point and the displaySize'
        public void Transform(PointF displayOrigin, SizeF displaySize)
        {
            matrix_bitmap.Reset();
            matrix_bitmap.Scale(displaySize.Width / (float)screen_size.Width, 
                displaySize.Height / (float)screen_size.Height);
            matrix_bitmap.Translate(displayOrigin.X, displayOrigin.Y, MatrixOrder.Append);
            inv_matrix_bitmap = matrix_bitmap.Clone();
            inv_matrix_bitmap.Invert();
        }


        // pretty obvious what they do
        //
        public void ScreenToBitmap(Point[] points)
        {
            matrix_bitmap.TransformPoints(points);
        }

        public void BitmapToScreen(Point[] points)
        {
            inv_matrix_bitmap.TransformPoints(points);
        }

        public void BitmapToWorld(Point[] points)
        {
            matrix_world.TransformPoints(points);
        }

        public void WorldToBitmap(Point[] points)
        {
            inv_matrix_world.TransformPoints(points);
        }

        public void ScreenToWorld(Point[] points)
        {
            ScreenToBitmap(points);
            BitmapToWorld(points);
        }

        public void WorldToScreen(Point[] points)
        {
            WorldToBitmap(points);
            BitmapToScreen(points);
        }
    }
}

Initialize the class by passing the appropriate sizes for your world (25,000x25,000) your bitmap (6,500x6,500) your picture box (1000x1000) and your origin point (a few milions if i remember well from your prevous post). In the initial state you must have your image drawn in the picture box by the graphics.DrawImage(bitmap, 0,0,1000,1000) call. When you want to zoom into a rectangle specified by two points taken from the mouse input (e.g pointMouseDown, pointMouseUp) first you transform these points to the original bitmap coords.

Point[] pts = new Point[]{pointMouseDown,pointMouseUp};
transformation.ScreenToBitmap(pts);
// and drawing
graphics.DrawImage(bitmap,new Rectangle(0,0,1000,1000), pts[0].X,pts[0].Y,pts[1].X-pts[0].X,
pts[1].Y-pts.[0].Y,GraphicUnit.Pixel);
// dont forget to inform transformation object for the zoom
transformation.Transform(pts[0],new Size(pts[1].X-pts[0].X,ts[1].Y-pts.[0].Y);

Whenever you want you can get the world coords of a screen point with the ScreenToWorld method and vice versa.
If you want to zoom out to the initial state just graphics.DrawImage(bitmap, 0,0,1000,1000) and call the Reset method of the transformation object.
\
Regards

Re: Drawing a big image to real coordinates

ianhunt012-Sep-08 5:49

ianhunt01

2-Sep-08 5:49

Awesome,

Thanks a lot - the whole matrix issue was a bit daunting but it makes more sense now. I will dig in right now and try it out.

cheers

Ian

Father class how to use the special sub-category type [modified]

huangrongchuan31-Aug-08 21:43

huangrongchuan

31-Aug-08 21:43

Father class how to use the special sub-category type (such as the sub-class form TableAdapter of a table), the current idea is traversal all the things on the form(such as traversing all controls on the sub-form), if found what I need, I want to transform its type into I want. But now what trouble me is i could not get the type neither trying to change the object into the type I needed nor using reflection to get the type. Thanks a lot.
Code is as follows:

private void findcontrol(Control.ControlCollection controls)
        {
            foreach (Control ctrl in controls)
            {
                if (ctrl.GetType().Name == "XXTableAdapter")
                {
                    //How to use the ctrl as XXTableAdapter to do something 
                    //just like this: TableAdapter.Update (customers DataTable); 
                    //the kind of type(XXTableAdapter) just could be founded on sub-class
                }
                findcontrol(ctrl.Controls);
            }
        }

Re: Father class in how to use the special sub-category of type

Guffa1-Sep-08 1:42

Guffa

1-Sep-08 1:42

Did you run your question through an automatic translator or something? I can hardly understand a thing.

Try again...

Despite everything, the person most likely to be fooling you next is yourself.

Re: Father class in how to use the special sub-category of type

huangrongchuan1-Sep-08 2:29

huangrongchuan

1-Sep-08 2:29

apologize for my poor english first,i have writen the question again ,could you understand what i want to say now

Re: Father class how to use the special sub-category type

Guffa1-Sep-08 6:38

Guffa

1-Sep-08 6:38

It would be better if you posted the actual code that you try to use. It's hard to tell which errors in the code comes from mistakes typing it in and which errors it is that cause the actual problem.

You can do like this to get access to controls of a specific type:

private void findcontrol(Control.ControlCollection controls) {
   foreach (Control ctrl in controls) {
      WhateverControlYouWant whatEver = ctrl as WhateverControlYouWant;
      if (whatEver != null) {
         // here you can use the whatEver variable
      }
      findcontrol(ctrl.Controls);
   }
}

Here's a generic version of the method, taking a type and a delegate for whatever to do with the control:

private void ProcessControls<T>(Control.ControlCollection controls, Action<T> action) {
   foreach (Control ctrl in controls) {
      T t = ctrl as T;
      if (t != null) {
         action(t);
      }
      ProcessControls<T>(ctrl.Controls, action);
   }
}

Usage example:

ProcessControls<Button>(this, delegate(Button b){ b.Enabled = false; });

Despite everything, the person most likely to be fooling you next is yourself.

modified on Monday, September 1, 2008 12:45 PM

Re: Father class how to use the special sub-category type [modified]

huangrongchuan1-Sep-08 15:45

huangrongchuan

1-Sep-08 15:45

Thanks a lot.I could understand the first example and i will improve my code.And i will try the second example since i haven`t used such kind of type(ProcessControls<t>).
But what truely trouble me now is the special type i want just could find on the sub-class.In my case,the XXTableAdapter was defind when i added a Dataset in the project.But when i designing the father class i could not used this type.

modified on Monday, September 1, 2008 10:06 PM

How to transfer all mails from one account to another.

ekpravasi31-Aug-08 20:18

ekpravasi

31-Aug-08 20:18

from gmail to aol, without change in any of message data....

Re: How to transfer all mails from one account to another.

Harvey Saayman31-Aug-08 20:41

Harvey Saayman

31-Aug-08 20:41

are you trying to do that in a C# program??

if so then id imagine youd have to use gmail's and aol's API's if they even have any...

Re: How to transfer all mails from one account to another.

ekpravasi31-Aug-08 21:13

ekpravasi

31-Aug-08 21:13

If we will use imap.... its possible or not? I gone through RFC3501(IMAP), also overviewed RFC2822(Internet Message format). But i am not getting any clue. I build connection and mail fetch program. but what next for tranfer?

Device ID

ellllllllie31-Aug-08 20:16

ellllllllie

31-Aug-08 20:16

Hello

Do someone know how to get the device id of a pocket PC?

Best regards

dghdfghdfghdfghdgh

Re: Device ID

Brij31-Aug-08 20:33

Brij

31-Aug-08 20:33

Please check this link
[^]

Cheers!!
Brij

Re: Device ID

ellllllllie31-Aug-08 23:45

ellllllllie

31-Aug-08 23:45

how do i deploy it to my pocket

dghdfghdfghdfghdgh

How to get commandline parameter from User

Laji5931-Aug-08 17:35

Laji59

31-Aug-08 17:35

I want to get a parameter(for example "Path of Data") from user in commandline.
How can I do it?

Hello Friends

Re: How to get commandline parameter from User

Vikram A Punathambekar31-Aug-08 18:34

Vikram A Punathambekar

31-Aug-08 18:34

Your Main method accepts a string array as a parameter. This contains what the user (or a shortcut) passed from the command line.

Cheers,
Vıkram.

"if abusing me makes you a credible then i better give u the chance which didnt get in real" - Adnan Siddiqi.

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