Deleting text from DrawText

[Phailak]

Hi,

Just want to know if there is a way to delete what one wrote with the API drawText without refreshing the screen or using the autoredraw. See, let's say I write Hello on a form and want it to write Bye in its place when user clicks a button, is there a way to delete Hello and then write again Bye.


Thanx

Phailak

Using refersh is the easy way, but if you want to erase it using API, I'm guessing you'd have to send the WM_PAINT and WM_ERASEBKGND messages.

[Phailak]

Ok, thanx,
Now let's say I have 10 areas define by the Api CreatePolygons and there is some text in each. What if I want to erase the text in one of the areas only, let's say Polygon number 5 (I do have its Rgn coordonates and those of the Rect i created to write my text into)
Can I still use those messages or will that erase the whole background?

Phailak

[gwdash]

you can do this ( i have the same problem, but this is my
solution, it works with a Rgn or a Rect structure):
Declares:

Public Declare Function RedrawWindow Lib "user32" (ByVal hwnd As Long, _
lprcUpdate As RECT, ByVal hrgnUpdate As Long, ByVal _
fuRedraw As Long) As Long

Public Declare Function RedrawWindowM Lib "user32" Alias "RedrawWindow" (ByVal hwnd As Long, lprcUpdate As _
Long, ByVal hrgnUpdate As Long, ByVal fuRedraw As Long) As _
Long

Public Declare Function DeleteObject Lib "gdi32" (ByVal _
hObject As Long) As Long


Public Const RDW_INVALIDATE = &H1

Public Const RDW_ERASE = &H4

Public Const RDW_ERASENOW = &H200

Public Const RDW_ALLCHILDREN = &H80

For Regions:

Private Sub ClearMessage(rgnBounding)
Dim retval As Long
RedrawWindowM 0, ByVal 0&, rgnBounding, RDW_INVALIDATE Or _
RDW_ERASE Or RDW_ERASENOW Or RDW_ALLCHILDREN 
'refresh screen only on that point
DeleteObject rgnBounding 'delete region
End Sub

For Rects:

Private Sub ClearBox(r As RECT)
RedrawWindow 0, r, ByVal 0&, RDW_INVALIDATE Or RDW_ERASE Or _
RDW_ERASENOW Or RDW_ALLCHILDREN 
'refresh screen only on that point
End Sub

[Phailak]

Thanx gwdash

I can work with those, it will probably erase my background right? But it doesn't matter, it will be easy to redraw

Phailak

[gwdash]

i probably will, but only right behind the text