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GDI+, as with the PB graphic commands allows me to draw outside a drawing area, IE a Graphic control.
How do I scroll to uncover the portion that is not displayed?
The attached code demonstrates what I mean. (Mostly derived from José Roca's most excellent Forum)
Here I draw vertical lines that start off inside the drawing area, but quickly exceed it's area
and most are drawn outside of the viewing area.
I had though that GdipTranslateWorldTransform would allow me to reposition the view origin and
a simple graphic refresh would give me what I want (as in clicking the 'Scroll button' in the top right), but of course it's not that simple. Nothing is with Windows.
Am I aproaching this in the wrong way? Do I have to handle it the same way as if using the
ordinary drawing API - IE something like ScrollwindowEX and then draw the uncovered portion?
I was hoping that GDI+ handled all this stuff.
How do I scroll to uncover the portion that is not displayed?
The attached code demonstrates what I mean. (Mostly derived from José Roca's most excellent Forum)
Here I draw vertical lines that start off inside the drawing area, but quickly exceed it's area
and most are drawn outside of the viewing area.
I had though that GdipTranslateWorldTransform would allow me to reposition the view origin and
a simple graphic refresh would give me what I want (as in clicking the 'Scroll button' in the top right), but of course it's not that simple. Nothing is with Windows.
Am I aproaching this in the wrong way? Do I have to handle it the same way as if using the
ordinary drawing API - IE something like ScrollwindowEX and then draw the uncovered portion?
I was hoping that GDI+ handled all this stuff.
Code:
#PBForms Created V1.51
'------------------------------------------------------------------------------
' The first line in this file is a PB/Forms metastatement.
' It should ALWAYS be the first line of the file. Other
' PB/Forms metastatements are placed at the beginning and
' end of "Named Blocks" of code that should be edited
' with PBForms only. Do not manually edit or delete these
' metastatements or PB/Forms will not be able to reread
' the file correctly. See the PB/Forms documentation for
' more information.
' Named blocks begin like this: #PBFORMS BEGIN ...
' Named blocks end like this: #PBFORMS END ...
' Other PB/Forms metastatements such as:
' #PBFORMS DECLARATIONS
' are used by PB/Forms to insert additional code.
' Feel free to make changes anywhere else in the file.
'------------------------------------------------------------------------------
#Compile Exe
'------------------------------------------------------------------------------
' ** Includes **
'------------------------------------------------------------------------------
#PBForms Begin Includes
%USEMACROS = 1
#If Not %Def(%WINAPI)
#Include "WIN32API.INC"
#EndIf
#If Not %Def(%COMMCTRL_INC)
#Include "COMMCTRL.INC"
#EndIf
#Include "PBForms.INC"
#PBForms End Includes
#Include "GDIPLUS.INC"
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
' ** Constants **
'------------------------------------------------------------------------------
#PBForms Begin Constants
%IDD_DIALOG1 = 101
%IDC_GRAPHIC1 = 1001
%IDC_Scroll = 1002
#PBForms End Constants
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
' ** Declarations **
'------------------------------------------------------------------------------
Declare CallBack Function ShowDIALOG1Proc()
Declare Function ShowDIALOG1(ByVal hParent As Dword) As Long
#PBForms Declarations
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
' ** Main Application Entry Point **
'------------------------------------------------------------------------------
Function PBMain()
PBFormsInitComCtls (%ICC_WIN95_CLASSES Or %ICC_DATE_CLASSES Or _
%ICC_INTERNET_CLASSES)
Local hr As Long
Local hDlg As Dword
Local token As Dword
Local StartupInput As GdiplusStartupInput
' Initialize GDI+
StartupInput.GdiplusVersion = 1
hr = GdiplusStartup(token, StartupInput, ByVal %Null)
If hr =-1 Then
MsgBox "Error initializing GDI+"
Exit Function
End If
ShowDIALOG1 %HWND_DESKTOP
End Function
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
' ** CallBacks **
'------------------------------------------------------------------------------
CallBack Function ShowDIALOG1Proc()
Local hDC As Dword
Local n As Single
Local hStatus As Long
Static pGraphics As Dword
Local pPen As Dword
Select Case As Long CbMsg
Case %WM_INITDIALOG
Graphic Get DC To hDC
hStatus = GdipCreateFromHDC(hdc, pGraphics)
hStatus = GdipSetPageUnit(pGraphics, %Unitinch) ' // Set the page units to inches
hStatus = GdipCreatePen1(GdiPlusMakeARGBColor(255, 0, 0, 0), 2, %UnitPixel, pPen) ' // Create a Pen
For n=1 To 150
GdipDrawLine pGraphics, pPen, n/10 , 0, n/10 , n/10 ' // Draw the line
Next n
' Graphic ReDraw
' // Cleanup
If pPen Then GdipDeletePen(pPen)
' If pGraphics Then GdipDeleteGraphics(pGraphics) 'This should be done on exit
Case %WM_NCACTIVATE
Static hWndSaveFocus As Dword
If IsFalse CbWParam Then
' Save control focus
hWndSaveFocus = GetFocus()
ElseIf hWndSaveFocus Then
' Restore control focus
SetFocus(hWndSaveFocus)
hWndSaveFocus = 0
End If
Case %WM_COMMAND
' Process control notifications
Select Case As Long CbCtl
'I expected **something** like this to work.
'Here's the question - how do I scoll to the part that is not displayed????
Case %IDC_Scroll
If CbCtlMsg = %BN_CLICKED Or CbCtlMsg = 1 Then
'Graphic Get DC To hDC
'hStatus = GdipCreateFromHDC(hdc, pGraphics)
'hStatus = GdipSetPageUnit(pGraphics, %Unitinch)
hStatus = GdipTranslateWorldTransform(pGraphics, 1, 0, %MatrixOrderPrepend)
Graphic ReDraw
End If
End Select
End Select
End Function
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
' ** Dialogs **
'------------------------------------------------------------------------------
Function ShowDIALOG1(ByVal hParent As Dword) As Long
Local lRslt As Long
#PBForms Begin Dialog %IDD_DIALOG1->->
Local hDlg As Dword
Dialog New hParent, "GDI+ Scrolling - It's a Mystery to me!", 70, 70, _
356, 248, %WS_POPUP Or %WS_BORDER Or %WS_DLGFRAME Or %WS_SYSMENU Or _
%WS_CLIPSIBLINGS Or %WS_VISIBLE Or %DS_MODALFRAME Or %DS_3DLOOK Or _
%DS_NOFAILCREATE Or %DS_SETFONT, %WS_EX_CONTROLPARENT Or %WS_EX_LEFT _
Or %WS_EX_LTRREADING Or %WS_EX_RIGHTSCROLLBAR, To hDlg
Control Add Graphic, hDlg, %IDC_GRAPHIC1, "", 50, 25, 295, 195, %WS_CHILD _
Or %WS_VISIBLE Or %WS_BORDER
Graphic Attach hDlg, %IDC_GRAPHIC1
Graphic Color %Black, %White
Graphic Clear
Control Add Button, hDlg, %IDC_Scroll, "Scroll", 5, 25, 40, 30
#PBForms End Dialog
Dialog Show Modal hDlg, Call ShowDIALOG1Proc To lRslt
#PBForms Begin CleanUp %IDD_DIALOG1
#PBForms End CleanUp
Function = lRslt
End Function
'------------------------------------------------------------------------------
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