Email Password Remember me?  Lost your password?

• Download demo project - 12.5 Kb

Introduction

In VC++ we have a class CRectTracker which helps drawing the trackers and also there is function a DrawFocusRect() with which tracker behavior can be achieved. In C# I did not find any kind of such functionality (if there is then I am unaware at the moment.). So I decided to make program which draw box with tracker and allows manipulation with the box with the help of trackers.

Key features

• Drawing trackers
• Moving the boxes having trackers attached to it.
• Resizing the box with the help of trackers.
• Selection is made in Z Order.

I tried to avoid Form�s Invalidate() function as it generates flickering effects and drawing is not smooth. I designed the program in a way to maximize the usage of double buffering to avoid flickering effect.

Using the code

Class CRectTracker

In the main program there are three modes of the program. First is the �None mode� which indicates that user is not drawing, second mode is the �Drawing mode� and it is invoked when user selects the Box icon from the toolbar and third is the �selection mode� it is invoked when user selects a box for changing the positioning or size.  

There is main bitmap which holds the current drawing. Whenever a change is required like drawing rubber band selection or drawing tracker a copy of the main bitmap is made and saved in TrackerImage bitmap and all the changes are made in it and in the end it is assigned to the main bitmap. Even when repaint is required then RePaintForm() function is called instead of calling paint() function of the form to avoid the flickering effect.

Conclusion

A simple program that demonstrates double buffering & tracker drawing is included. OnPaint() generates flickering effects so it is recommended to draw first on the bitmap and then on the form.

You must Sign In to use this message board.

Per page 102550

FirstPrevNext

I can't open the demo code. Better code idea? Member 3390864 7:18 4 Jul '09   I can't open the demo code. I have VB net installed. Is it possible to convert code to vb net? . Does anyone know about geometric picking objects using distance criterion method? I'd like to develope a simple public GDI lib that you can select and edit a simple objects like line, polyline, ellipse... by clicking mouse. I know for old DOS system, this was discovered and developed very well decades ago. I don't know GDI lib for .net has those functions built-in or it was ignored and leave the burden to developer to figure it out. If that the case then I have to start to work on it from base zero. Any idea would be appreciate. Sign In·View Thread·PermaLink My vote of 1 Mrtnk 1:26 25 Jun '09   Not useful Sign In·View Thread·PermaLink draw a rectangle on image Babita Shivade 2:14 29 Apr '09   hi frind this code is working for form, I want use picturebox and want to draw rectangle on its image . can this code work or not thanks Sign In·View Thread·PermaLink how to add a tracker for a bit map sandun neelanga 0:09 31 Oct '07   I'm using vs 2005 C++ MFC application i want to load a bitmap,GIFF,JPG(any image) from a file and want to implement a tracker to the bit map. For resizing Can anybody explain how to do this Thanks Thilani Sign In·View Thread·PermaLink Re: how to add a tracker for a bit map 00thilani 7:41 2 Jan '08   I was able to implement this using CRectTracker and GDI+ Sign In·View Thread·PermaLink 1.00/5 source code Raja Sekhar Bandaru 15:31 25 Apr '07   hi, I am new to MFC. so can you please give me the source code of this project thanks in advance luv and luk raja sekhar bandaru Sign In·View Thread·PermaLink 1.00/5 Re: source code khurram7t8 22:27 25 Apr '07   It is attached to the project. click the download link above the project drawing picture. Sign In·View Thread·PermaLink how to delete a selected object? yuxuant 20:28 31 Oct '05   Thanks a lot! Sign In·View Thread·PermaLink Re: how to delete a selected object? khurram7t8 7:31 5 Nov '05   Hi I did not design this program for the deletion of the objects. this program is only for the demonstration of trackers. if i get a chance i'll improve it in future. Thanks Khurram Sign In·View Thread·PermaLink thanks! I have a question xu xiaodong 4:24 7 Jun '04   when the application running and i draw a rectangle,i find that about 50M memory is occupied.how to deal with this problem? Live and learn Sign In·View Thread·PermaLink Re: thanks! I have a question khurram7t8 19:49 8 Jun '04   Yes that is true when u start drawing the rectangle it takes memory and you must have seen the code to know why it happened. in C# trackers cannot be drawn directly so if i use the traditional approach of drawing (by drawing one rect then clearing it and again drawing that rectangle with different values) then the effect of drawing of rect will be full of flickering and believe me it is really bad that is why i used the double buffering method. here u can apply some optimization techniques. for example 1. On every mouse change event one bitmap is made and drwing is done on it and previous bitmap is deleted. u can increase the interval of this event, for example write a code which is executed only when mouse change is significant. right now it draws when one pixle change is detected u can increase the no of pixel to 2 or more on which the event should occur. 2. currently bitmap size is equal to the size of the form. create bitmap equal to the size of the drawing rect and draw this bitmap where the user is drawing the new rectanlge. it will definetly decrease the bitmap size. Sign In·View Thread·PermaLink Excellent cql60 10:06 21 Nov '03   Thanks you so much for such wonderful source code, I m looking for this such a long time. Keep it up the good work. Kate Sign In·View Thread·PermaLink Re: Excellent Nickle 11:19 18 Jan '04   I'll second that! Sign In·View Thread·PermaLink Thanks Xboss 21:22 30 Sep '03   I was searching for this script for a long time. Thanks for the post. But i saw this code only after developing my own control which fixes most of the bugs found in this script. I'll be posting that code here after some more finishing touches. Sign In·View Thread·PermaLink 1.00/5 Drawing a Tracker Jay Giganti 6:23 12 Sep '03   There is a method in C# which will draw a tracker it can be called as follows ControlPaint.DrawReversibleFrame(Rectangle, BackColor, FrameStyle); ControlPaint is in the System.Windows.Forms namespace. Basically call it the first time to draw it, then call it a second time to erase it. Sign In·View Thread·PermaLink 1.50/5 thanks birol.bellikan@kibarholding.com 2:22 27 Jun '03   thank you a lot Sign In·View Thread·PermaLink Thanks! Joost Huizinga 4:31 11 Jun '03   Thank you very much ! I was looking for such a script! Sign In·View Thread·PermaLink multiple selection & group move Dan Colasanti 9:05 6 Jun '03   A couple other ideas for enhancement: (1) multiple selection of rectangles (eg. using the CTRL/SHIFT keys and/or rubberbanding) (2) moving multiply-selected items Good luck! Dan Sign In·View Thread·PermaLink 5.00/5 corner resizers & Z-order selection problems Dan Colasanti 8:58 6 Jun '03   Hello, This looks good but there seem to be a couple minor bug fixes and additions that would make it better... (1) The corner resizers are non-operable (only the side resizers seem to work). (2) When two or more rectangles overlap and the user selects a point in the overlapped area, the last created rectangle is selected (which is correct since it by default has the highest Z-Order). But it would be useful to allow the ability to change the Z-order of the rectangles (maybe using a popup menu). (3) Along this same line of thought as point #2, it may be useful to have the programmatic option so that a selected item defies the Z-Order (so that if you click a point within a selected rectangle that also falls within a rectangle of a higher Z-Order, that the selected rectangle takes precedence and remains selected). I think this is a better option than forcing the selected object to the top of the Z-Order because that could cause layering problems in non-transparent objects. Dan Sign In·View Thread·PermaLink 5.00/5 Re: corner resizers & Z-order selection problems khurram_manglian@yahoo.com 17:48 6 Jun '03   Thanx for viewing the article and suggestions 1. the project is made for demo purpose. u can very easily modify the program to make box resizable from any corner or edge. u have to enter code in a switch statement in MouseMove code. 2. also Z-Order issue can easily be solved. making a wrapper class which will have Head and Tail nodes, and sorting the linked list according to user's choice. Thank you and i am greatfull for yout comments and suggestions. Sign In·View Thread·PermaLink Re: corner resizers & Z-order selection problems Nickle 11:18 18 Jan '04   You need to change some things for the corners.. First the enumerations.... enum RESIZE_BORDER// keep track of which border of the box is to be resized. { RB_NONE = 0, RB_TOP = 1, RB_RIGHT = 2, RB_BOTTOM = 3, RB_LEFT = 4, RB_TOPLEFT = 5, RB_TOPRIGHT = 6, RB_BOTTOMLEFT = 7, RB_BOTTOMRIGHT = 8 } Second setting the expand the Form1_MouseDown to include the new cursors this.Cursor == Cursors.SizeNESW or this.Cursor == Cursors.SizeNWSE case MOUSE_MODE.MM_OBJ_SELECTED: { if(m_enMM == MOUSE_MODE.MM_OBJ_SELECTED && (this.Cursor == Cursors.SizeNS || this.Cursor == Cursors.SizeWE || this.Cursor == Cursors.SizeNESW || this.Cursor == Cursors.SizeNWSE )) { return; // do nothing, it requires resizing of the selected object. } Modify Cursor CursorCheck(Rectangle rc, Point pt, ref int enResult) to include the corner selection points... Add to the end.... else if(m_TopLeft.Contains(pt)) { enResult = 5; return Cursors.SizeNWSE; } else if(m_TopRight.Contains(pt)) { enResult = 6; return Cursors.SizeNESW; } else if(m_BottomLeft.Contains(pt) ) { enResult = 7; return Cursors.SizeNESW; } else if(m_BottomRight.Contains(pt)) { enResult = 8; return Cursors.SizeNWSE; } else return Cursors.Default; Then modify Form1_MouseMove to include the corners.... switch(this.m_enRBorder) { case RESIZE_BORDER.RB_TOP: SelectedNode.rc.Height = SelectedNode.rc.Y + SelectedNode.rc.Height - e.Y; SelectedNode.rc.Y = e.Y; break; case RESIZE_BORDER.RB_TOPLEFT: SelectedNode.rc.Height = SelectedNode.rc.Y + SelectedNode.rc.Height - e.Y; SelectedNode.rc.Y = e.Y; SelectedNode.rc.Width = SelectedNode.rc.X + SelectedNode.rc.Width - e.X; SelectedNode.rc.X = e.X; break; case RESIZE_BORDER.RB_TOPRIGHT: SelectedNode.rc.Height = SelectedNode.rc.Y + SelectedNode.rc.Height - e.Y; SelectedNode.rc.Y = e.Y; SelectedNode.rc.Width = e.X - SelectedNode.rc.X; break; case RESIZE_BORDER.RB_RIGHT: SelectedNode.rc.Width = e.X - SelectedNode.rc.X; break; case RESIZE_BORDER.RB_BOTTOM: SelectedNode.rc.Height = e.Y - SelectedNode.rc.Y; break; case RESIZE_BORDER.RB_BOTTOMLEFT: SelectedNode.rc.Height = e.Y - SelectedNode.rc.Y; SelectedNode.rc.Width = SelectedNode.rc.X + SelectedNode.rc.Width - e.X; SelectedNode.rc.X = e.X; break; case RESIZE_BORDER.RB_BOTTOMRIGHT: SelectedNode.rc.Height = e.Y - SelectedNode.rc.Y; SelectedNode.rc.Width = e.X - SelectedNode.rc.X; break; case RESIZE_BORDER.RB_LEFT: SelectedNode.rc.Width = SelectedNode.rc.X + SelectedNode.rc.Width - e.X; SelectedNode.rc.X = e.X; break; } should work then Sign In·View Thread·PermaLink Any chance doing this in C++? WREY 3:28 6 Jun '03   Flickering is one of those things that ranks right up there as a developer's worst nightmare. If this is one technique that helps in that department, I'm all for it. Any chance you can come up with a C++ sample? William Fortes in fide et opere! Sign In·View Thread·PermaLink Re: Any chance doing this in C++? SledgeHammer 6:18 6 Jun '03   A almost real good example of am OOD draw sample can be found in the MFC Samples look for DrawCli, it's quite easy to implement you own Object drawing framework, I'm current completing a project which always the user to place cells on a canvas, quite similar to Visio. Once you get basic cells on the canvas, the tricky bits are Pan and Zoom and I'd love to see this implemented in .net without resorting to importing a raft of reference to USER32.DLL and GDI32.DLL - just a thought? To iterate is human, to recurse is devine. Sign In·View Thread·PermaLink 3.00/5

Last Visit: 5:55 22 Nov '09     Last Update: 5:55 22 Nov '09 1