Form re-paint GDI+

Question

I have a form which i am painting a custom interface for (I.E Skinning it)

However i have one issue which is:

I am painting the title bar, minimize, maximize and close buttons manually. I paint these on using the graphics object and all looks fine and dandy. However i have one small issue. When someone hovers over say the close button i need to change the image that has been painted in that area. The only way i can see to do this is:

1. create a picture boxe in the location for the close button and change the image depending on the mouse state which could be clunky.
2. repaint the form and paint the correct image in its place. However repainting the entire form for just one button state is a bit heavy and could be very slow. Although it would give me what i want it would not give the user a good experience in the app.

Is there any way of re-painting just a specific area of the form or do i really have to go with a picturebox and change the image depending on the mouse state?

Cheers

jinge · Answer

If you draw on the form you need to invalidate the form to get your close button updated. The way I suggest you put the close button in a usercontrol can mitigate the problem. Only invalidate the usercontrol will be Ok.

Giles Papworth · Answer

I will be doing if i get stuck with it. Again thanks for the help

jinge · Answer

If you have new problems wish you could start a new thread.

Giles Papworth · Answer

The only issue i have now is the speed of the paint on the user control it is only mildly sped up by double buffering the control. I could replace the paint with a picture box but not sure that will have any improvement on the performance of the control and unsure as to the memory implications as well. Ah sometimes i wish i didn't embark on these sorts of projects but well it is the only way to learn.

jinge · Answer

You are welcome. I want to share you with a client tool I just created which can notify me when there's any change in this forum. I will update the link in my signiture later on.

Giles Papworth · Answer

Forgive me i was being a bit stupid i was using some weird property from the form not sure why again must have been because i was doing this in a hurry to get a quick demo out to someone to show them how skinning a form should be done instead of creating hundreds of picture boxes on a form. Thanks for your help again and for the idea's.

jinge · Answer

Base class defines common behaviors for its all inheritors. You don't have to get Text Property of its inheritors. When you set the Text property of the base form the inherited form just get it by default. Sure you can override it in the inheritors.

Giles Papworth · Answer

Great that seems to work fine :). Only one issue is that it is a bit slow but i am sure i can find a way around that. Next and last quick question as this form is designed to be a base object and other forms inherited off it is there any way of getting the value of the text property from the inherited object? Cheers

jinge · Answer

Ok if you have any problem let me know.

Giles Papworth · Answer

Jinge That actually is not a bad idea i didn't think of that i can hold all the repainting stuff in the user control you know that situation where you cannot see the wood for the trees? Yep! Im going to give that a try and see where it leads me cheers for that!

Giles Papworth · Answer

I mean i have some code that works: The loadskin() method only gets run if the boolean LoadedSkin is false and obviously if the form is repainted. When the user hovers over where i have painted the close button the code detects this sets the loaded skin to false a boolean to say that the close button has changed and then invalidate the form. The LoadSkin then sees the close button boolean is true loads the hover image accordingly and then repaints the entire form. This does work splendidy but repainting is quite heavy especially if i am doing the entire form. All the images are already loaded into memory so its not as if it has to get them all out of the skin file again.

Giles Papworth · Answer

My issue is that i need to draw these with custom graphics really. Implementing the actual functions of these buttons is fairly easy detecting where the mouse was clicked and then checking the coords with where the buttons are is extreemly easy. Its just the re-draw on the mouse states that i am having issues with. It would be usefull to just re-draw the area where the button is without having to re-draw the whole form. With big forms this could be very counter productive. As per the Glassbutton link posted before i know this can be done but looking through the code it does seem to re-paint the whole control if im not mistaken?

jinge · Answer

Hi friend You can create a UserControl with minmaxclose button this can restrict the redrawing in the usercontrol level. Let me know if you have any concern.

Giles Papworth · Answer

It is all painted by me. The code of the onpaint is below. Please note that i am still developing this so code is...well not perfect. protected override void OnPaint(System.Windows.Forms.PaintEventArgs pe) { if (!DesignMode && Storage.LoadedSkin.currentSkin != null) { LoadSkin(); Brush t = new TextureBrush(titleBarGraphic); pe.Graphics.FillRectangle(new SolidBrush(Color.FromArgb(27 27 27)) new Rectangle(0 0 this.Width this.Height)); pe.Graphics.FillRectangle(new SolidBrush(Storage.LoadedSkin.currentSkin.Form_BackgroundColor) new Rectangle(2 2 this.Width - 4 this.Height - 4)); try { pe.Graphics.FillRectangle(t new Rectangle(0 0 this.Width Storage.LoadedSkin.currentSkin.Form_TitleBarHeight)); } catch { } t = null; try { pe.Graphics.DrawImage(closeButton this.Width - 2 - Storage.LoadedSkin.currentSkin.Form_CloseButtonWidth 1 Storage.LoadedSkin.currentSkin.Form_CloseButtonWidth Storage.LoadedSkin.currentSkin.Form_CloseButtonHeight); closeButtonLocation.X } catch { } try { pe.Graphics.DrawImage(maxButton this.Width - 2 - (Storage.LoadedSkin.currentSkin.Form_CloseButtonWidth + Storage.LoadedSkin.currentSkin.Form_MaximizeButtonWidth) - 1 1 Storage.LoadedSkin.currentSkin.Form_MaximizeButtonWidth Storage.LoadedSkin.currentSkin.Form_MaximizeButtonHeight); } catch { } try { pe.Graphics.DrawImage(minButton this.Width - 2 - (Storage.LoadedSkin.currentSkin.Form_CloseButtonWidth + Storage.LoadedSkin.currentSkin.Form_MaximizeButtonWidth + Storage.LoadedSkin.currentSkin.Form_MinimizeButtonWidth) - 1 1 Storage.LoadedSkin.currentSkin.Form_MinimizeButtonWidth Storage.LoadedSkin.currentSkin.Form_MinimizeButtonHeight); } catch { } SizeF textSize = pe.Graphics.MeasureString(formText DisplayFont); Int32 textWidth = (int)textSize.Width + 2; StringFormat sFormat = new StringFormat(); sFormat.LineAlignment = StringAlignment.Center; Rectangle wrapTangle = new Rectangle(0 0 textWidth Storage.LoadedSkin.currentSkin.Form_TitleBarHeight); pe.Graphics.DrawString(formText DisplayFont new SolidBrush(Color.White) wrapTangle sFormat); } else { pe.Graphics.DrawString(No Skin Loaded new Font(Arial 10) Brushes.RoyalBlue new PointF(30.0F 50.0F)); } } As you can see i am painting all the buttons. The form is set to have no border so i can do the form painting myself.

Kirtan Patel · Answer

are you painting on your own buttons in form or Close Button that are by default provided ???

Giles Papworth · Answer

Yea i have seen this button before must dig deeper into the code. Very well made button could do with a little more commenting though. But i can see where i need to get the code from. I am assuming at this point that there is some sort of graphics buffer it draws to and from to ansure that only certain bits are updated.

Kirtan Patel · Answer

my be below link can help you :) http://www.codeproject.com/KB/buttons/glassbutton.aspx