I used a panel in the Winform draw some geometry, a polygon and rectangle and string, now I want to part choose delete from the graphics, my idea is on the geometric figure then get a transparent extendedPanel1, draw the mouse in the extendedPanel1 checkbox (similar to Windows file selection), and according to the coordinates and whether the area calculation of the bottom panel graphics in this area, so as to determine repainting panel,
Below is the graphics and code:
Red is I draw a geometric figure, green is the mouse choose rendering rectangle, the question now is, in the mouse choose many rectangle, extendedPanel1 is a new panel, give his inheritance in it defines transparency, now every time a new draw the mouse rectangular box box still exists in the previous step, even if I use Invalidate or doesn't work, if there is no transparency, you can achieve this choice, also is the same as other drawing software, but as a result of extendedPanel1 is transparent, every time just reload, but inside painting figure don't disappear, tried the cancel controls also doesn't fit, I don't know how to solve, or do you have a better solution? (but in winform)

//a new definition of transparent panel 
Public class ExtendedPanel: Panel 
{
Private const int WS_EX_TRANSPARENT=0 x20; 
Public ExtendedPanel () 
{
SetStyle (ControlStyles. Opaque, true); 
} 

Private int opacity=0; 
[DefaultValue (0)) 
Public int Opacity 
{
The get 
{
Return this. The opacity; 
} 
Set 
{
If (value & lt; 0 | | value & gt; 100) 
Throw new ArgumentException (" value must be between 0 and 100 "); 
This. Opacity=value; 
} 
} 
Protected override CreateParams CreateParams 
{
The get 
{
CreateParams cp=base. CreateParams; 
Cp. ExStyle=cp. ExStyle | WS_EX_TRANSPARENT; 
Return the cp; 
} 
} 
Protected override void OnPaint (PaintEventArgs e) 
{
Using (var brush=new SolidBrush (Color FromArgb (enclosing opacity * 255/100, enclosing BackColor))) 
{
Um participant raphics. FillRectangle (brush, enclosing ClientRectangle); 
} 
Base. The OnPaint (e); 
} 
} 

//mouse code 
Private void SetSelectionRect () 
{
int x, y; 
Int width, height; 

X=selectionStart. X & gt; SelectionEnd. X? SelectionEnd. X: selectionStart. X; 
Y=selectionStart. Y & gt; SelectionEnd. Y? SelectionEnd. Y: selectionStart. Y; 

Width=selectionStart. X & gt; SelectionEnd. X? SelectionStart. X-ray selectionEnd. X: selectionEnd) X - selectionStart. X; 
Height=selectionStart. Y & gt; SelectionEnd. Y? SelectionStart. Y - selectionEnd. Y: selectionEnd) - selectionStart. Y Y; 

Selection=new Rectangle (x, y, width, height); 
} 

Private void extendedPanel1_Paint (object sender, PaintEventArgs e) 
{
Base. The OnPaint (e); 
ExtendedPanel1. Opacity=0; 
If (mouseDown) 
{
Using (Pen Pen=new Pen (Color Green, 1 f)) 
{
Pen. DashStyle=DashStyle. Dash; 
Um participant raphics. DrawRectangle (pen, selection); 
} 
} 
} 

Private void extendedPanel1_MouseDown (object sender, MouseEventArgs e) 
{
SelectionStart=extendedPanel1. PointToClient (MousePosition); 
MouseDown=true; 
} 

Private void extendedPanel1_MouseUp (object sender, MouseEventArgs e) 
{
MouseDown=false; 
SetSelectionRect (); 
ExtendedPanel1. Invalidate (); 
} 

Private void extendedPanel1_MouseMove (object sender, MouseEventArgs e) 
{
if (! MouseDown) 
return; 
SelectionEnd=extendedPanel1. PointToClient (MousePosition); 
SetSelectionRect (); 
ExtendedPanel1. Invalidate (); 
} 

CodePudding user response:

. Give you an idea of the Mouse Move event to do the following:
After 1, draw new selection box, to save the rectangular box temporarily, for subsequent use
Before 2, draw new selection box, remove the step 1 to draw the selection box, otherwise, like your screenshot, leaving many of residual box before
3, can study the ControlPaint DrawReversibleFrame (), it is a rectangular box drawing method

CodePudding user response:

Will draw a box on the original image, put a background and the relationship between the state of the object, is the state object manipulation, such as defining a Border of the object, which contains the graphic data width coordinates radius, z axis or depth, etc., if the mouse is moved to a box, it changes the state of the corresponding object value, borders drawn according to need, delete a box, just remove the object,