Please note: The large size of the downloads is caused by the images included with the demo project. The compiled .dll library is only 44Kb.
As a minor part of the image processing sub-system of my project I needed a way to allow users to select an identifying region on the set of images they are working with. This region for each individual image is then to be shown at magnification (as compared to the full/cropped images shown as thumbnails).
While my need was very specific -- I wanted to know the co-ordinates of a rectangle selected on the surface of a PictureBox control -- I decided to write a more versatile class which should be able to draw a rectangle on any object which inherits from System.Windows.Forms.Control and return the rectangle co-ordinates to the invoking program.
The class I wrote to accomplish this goal is: TdhMarchingAnts_NativeWindow. This class may be used by instantiating it directly via code.
I also wrote a component class, TdhMarchingAnts, to act as a development-environment "wrapper" for TdhMarchingAnts_NativeWindow.
The demo program uses/tests both classes.
To use the TdhMarchingAnts classes as I've written them, add a reference in your project to the class library 'TDHMarchingAnts.dll.' The namespace used in this library is:
using TDHControls.TDHMarchingAnts;
An example of 'Windows Form Designer generated code' for the TdhMarchingAnts component is:
private void InitializeComponent()
{
this.tdhAnts
= new TDHControls.TDHMarchingAnts.TdhMarchingAnts(this.components);
//
// tdhAnts
//
this.tdhAnts.AntAttachedControl = this.pnlDemo;
this.tdhAnts.AntBackColor = System.Drawing.Color.Black; // default: .White
this.tdhAnts.AntForeColor = System.Drawing.Color.White; // default: .Red
this.tdhAnts.AntsActive = true; // Note: this is 'false' by default
this.tdhAnts.RegionDeselectEvent += new
TDHControls.TDHMarchingAnts.RegionDeselectEventHandler(this.tdhAnts_RegionDeselectEvent);
this.tdhAnts.RegionSelectEvent += new
TDHControls.TDHMarchingAnts.RegionSelectEventHandler(this.tdhAnts_RegionSelectEvent);
}
Example code for instantiating the TdhMarchingAnts_NativeWindow class independently of the TdhMarchingAnts component is:
private TDHControls.TDHMarchingAnts.TdhMarchingAnts_NativeWindow native_PicBox;
private TDHControls.TDHMarchingAnts.TdhMarchingAnts_NativeWindow native_Panel;
{
this.native_PicBox
= new TDHControls.TDHMarchingAnts.TdhMarchingAnts_NativeWindow(this.pbxImage);
this.native_PicBox.AntsActive = true; // Note: this is 'false' by default
this.native_PicBox.RegionSelectEvent += new
TDHControls.TDHMarchingAnts.RegionSelectEventHandler(this._PicBox_RegionSelectEvent);
this.native_PicBox.RegionDeselectEvent += new
TDHControls.TDHMarchingAnts.RegionDeselectEventHandler(this._PicBox_RegionDeselectEvent);
// The Constructor also accepts the "left-Ant" fore- and back- colors
this.native_Panel
= new TDHControls.TDHMarchingAnts.TdhMarchingAnts_NativeWindow
(this.pnlForSomething, Color.Blue, Color.Yellow);
}
The TdhMarchingAnts_NativeWindow class and the TdhMarchingAnts component raise potentially six events (that is, three each for either mouse button).
Assuming the appropriate boolean properties are true, the event _RegionSelectEvent() (and corresponding event _RightRegionSelectEvent()) is raised when the left (or right) mouse button is released following a "click-and-drag."
Assuming the appropriate boolean properties are true, the events _ClickEvent() and _RegionDeselectEvent() (and corresponding events _RightClickEvent() and _RightRegionDeselectEvent()) are raised when the left (or right) mouse button is clicked. Thus, _ClickEvent() (or _RightClickEvent()) may be raised either alone or in conjuction with _RegionDeselectEvent() (or _RightRegionDeselectEvent()).
The signatures of the event handler methods are as follows:
private void _ClickEvent(object sender, System.Drawing.Point ClickedPoint)
{
// do something (assuming you care about this event)
}
private void _RegionDeselectEvent(object sender, System.Drawing.Point ClickedPoint)
{
// do something (assuming you care about this event)
}
private void _RegionSelectEvent(object sender, System.Drawing.Rectangle SelectedRect)
{
// do something (surely you do care about this event!)
}
private void _RightClickEvent(object sender, System.Drawing.Point ClickedPoint)
{
// do something (assuming you care about this event)
}
private void _RightRegionDeselectEvent(object sender, System.Drawing.Point ClickedPoint)
{
// do something (assuming you care about this event)
}
private void _RightRegionSelectEvent(object sender, System.Drawing.Rectangle SelectedRect)
{
// do something (surely you do care about this event!)
}
Please note: With version 1.0.004, the signatures of all the event handler methods have been changed (I apologize if this causes an inconvenience). The event handler parameter-lists should have included "object sender" originally.
Beginning with version 1.0.002, the TdhMarchingAnts classes may be used with either the left mouse button or the right (or both). The "default" button is the left: that is, the previously named properties, methods and events are defined for mouse left-button activity; the corresponding properties, methods and events defined for mouse right-button activity are preceded with the word "Right_" (for properties and methods) or "Right" (for events).
Both the TdhMarchingAnts component and the TdhMarchingAnts_NativeWindow class have essentially the same public interface:
TdhMarchingAnts component class are:
System.Drawing.Point ReallyEmptyPoint() - This method returns a System.Drawing.Point object with .X and .Y properties set to -1.
IsReallyEmptyPoint(System.Drawing.Point pt) - This method returns 'true' if the .X and .Y properties of the System.Drawing.Point object 'pt' both equal -1, else it returns 'false.'
System.Drawing.Rectangle ReallyEmptyRectangle() - This method returns a System.Drawing.Rectangle object with .X, .Y, .Width and .Height properties set to -1.
IsReallyEmptyRectangle(System.Drawing.Rectangle rec) - This method returns 'true' if the .X, .Y, .Width and .Height properties of the System.Drawing.Point object 'rec' all equal -1, else it returns 'false.' AntAttachedControl - (I'm sorry about the property's name, but I wanted it to be alphabetically first so that the auto-generated code will set it first) This property is used to attach the instance of TdhMarchingAnts_NativeWindow to a specific control.
Enabled - This boolean value determines whether the class as a whole is enabled/active and thus responsive to the user's mouse activity. AntsActive - This boolean value determines whether the class is responsive to the user's mouse left-button select and deselect activity.
AntBackColor - The System.Drawing.Color of the path followed by the "ants" determined by mouse left-button select activity.
AntBackColor before setting AntForeColor. When AntBackColor is set, the class automatically sets AntForeColor to a (hopefully ideal) contrasting color. AntForeColor - the System.Drawing.Color of the "ants" (themselves) determined by mouse left-button select activity.
AntForeColor to the same vaue that AntBackColor was previously set. (Alternately, this may be accomplished via the ExterminateAnts() method.) AntsMarch - This boolean value determines whether the "ants" determined by mouse left-button select activity will be animated.
SelectedPointTL - This property returns a System.Drawing.Point representing the top-left co-ordinate of the selected region. If there is not yet a selected region, the .X and .Y values are -1.
SelectedPointBR - This property returns a System.Drawing.Point representing the bottom-right co-ordinate of the selected region. If there is not yet a selected region, the .X and .Y values are -1.
SelectedRect - This property returns a System.Drawing.Rectangle representing the selected region. If there is not yet a selected region, the .Width and .Height values are -1. EraseAntPath() - This method removes the visual representation of the selected region, while retaining the rectangle co-ordinates themselves.
ForgetAntPath() - This method removes the visual representation of the selected region *and* disposes of the rectangle co-ordinates.
ExterminateAnts() - This method sets AntForeColor to the current value of AntBackColor -- i.e. it changes the drawn rectangle to a solid line.
SetAntPath(System.Drawing.Rectangle PathRect) - This method draws a rectangle on the attached control with the co-ordinates of the given rectangle.
RegionSelectEvent' as though the user had selected the region represented by the rectangle. public delegate void ClickEventHandler(object sender, System.Drawing.Point ClickedPoint) - [If (.Enabled=true)] This event occurs when the user left-clicks on the control attached to the TdhMarchingAnts component.
public delegate void RegionDeselectEventHandler(object sender, System.Drawing.Point ClickedPoint) - [If (.Enabled=true) and (.AntsActive=true) and a region is currently selected] This event occurs when the user left-clicks on the control attached to the TdhMarchingAnts component.
ClickEvent and RegionDeselectEvent events are raised. public delegate void RegionSelectEventHandler(object sender, System.Drawing.Rectangle SelectedRect) - [If (.Enabled=true) and (.AntsActive=true)] This event is raised when the left mouse button is released following a "click-and-drag." Right_AntsActive - This boolean value determines whether the class is responsive to the user's mouse right-button select and deselect activity.
Right_AntBackColor - The System.Drawing.Color of the path followed by the "ants" determined by mouse right-button select activity.
AntBackColor before setting AntForeColor. When AntBackColor is set, the class automatically sets AntForeColor to a (hopefully ideal) contrasting color. Right_AntForeColor - the System.Drawing.Color of the "ants" (themselves) determined by mouse right-button select activity.
AntForeColor to the same vaue that AntBackColor was previously set. (Alternately, this may be accomplished via the ExterminateAnts() method.) Right_AntsMarch - This boolean value determines whether the "ants" determined by mouse right-button select activity will be animated.
Right_SelectedPointTL - This property returns a System.Drawing.Point representing the top-left co-ordinate of the selected region. If there is not yet a selected region, the .X and .Y values are -1.
Right_SelectedPointBR - This property returns a System.Drawing.Point representing the bottom-right co-ordinate of the selected region. If there is not yet a selected region, the .X and .Y values are -1.
Right_SelectedRect - This property returns a System.Drawing.Rectangle representing the selected region. If there is not yet a selected region, the .Width and .Height values are -1. Right_EraseAntPath() - This method removes the visual representation of the selected region, while retaining the rectangle co-ordinates themselves.
Right_ForgetAntPath() - This method removes the visual representation of the selected region *and* disposes of the rectangle co-ordinates.
Right_ExterminateAnts() - This method sets Right_AntForeColor to the current value of Right_AntBackColor -- i.e. it changes the drawn rectangle to a solid line.
Right_SetAntPath(System.Drawing.Rectangle PathRect) - This method draws a rectangle on the attached control with the co-ordinates of the given rectangle.
RightRegionSelectEvent' as though the user had selected the region represented by the rectangle. public delegate void RightClickEventHandler(object sender, System.Drawing.Point ClickedPoint) - [If (.Enabled=true)] This event occurs when the user right-clicks on the control attached to the TdhMarchingAnts component.
public delegate void RightRegionDeselectEventHandler(object sender, System.Drawing.Point ClickedPoint) - [If (.Enabled=true) and (.Right_AntsActive=true) and a region is currently selected] This event occurs when the user right-clicks on the control attached to the TdhMarchingAnts component.
RightClickEvent and RightRegionDeselectEvent events are raised. public delegate void RightRegionSelectEventHandler(object sender, System.Drawing.Rectangle SelectedRect) - [If (.Enabled=true) and (.Right_AntsActive=true)] This event is raised when the right mouse button is released following a "click-and-drag." TdhMarchingAnts ver 1.0.001 to The Code Project.
ClickEvent(object sender, System.Drawing.Point ClickedPoint)
RightClickEvent(object sender, System.Drawing.Point ClickedPoint)
RightRegionSelectEvent(object sender, System.Drawing.Rectangle SelectedRect)
RightRegionDeselectEvent(object sender, System.Drawing.Point ClickedPoint) TdhMarchingAnts_NativeWindow to class TdhMarchingAnts (and made them 'public'):
System.Drawing.Point ReallyEmptyPoint()
IsReallyEmptyPoint(System.Drawing.Point pt) TdhMarchingAnts:
System.Drawing.Rectangle ReallyEmptyRectangle()
IsReallyEmptyRectangle(System.Drawing.Rectangle rec) | You must Sign In to use this message board. | |||||
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I hope you're able to pull it off (and if you do, be sure to submit an article). 
