Requires: Direct2D.lg32
Converts physical pixels to Direct2D's DIP coordinate system (and vice cersa) for the current render target or Me.
Dip! = D2PixelsToDIP(Pixels!)
Pixels! = D2DIPsToPixel(Dip!)
| Pixels!, Dip! | : float expression |
On high-resolution displays the number of pixels do not match the number of DIPs (device independent pixels <=> 1/96 inch) as it does on a regular 96 dots-per-inch display. This not a problem with a dpi-unaware program; Windows makes sure the program's coordinate system matches the 96 dots-per-inch coordinate system and there is no need to convert physical pixels to DIPs. When the program is dpi-aware the program uses the display's full Dpi as a coordinate system. Mouse input is provided in the display's Dpi. D2PixelsToDIP helps in converting the physical pixel value to Direct2D's DIP coordinate system, while D2DIPsToPixel performs the reverse conversion.
'
' Samples\Direct2D\D2PixelsToDIP.g32
' (dpi-aware)
'
$Library "direct2d"
$Library "gfawinx"
DpiAwareness()
Global Object Win1RT
OpenW 1, 0, 0, 320, 260, ~15
FormScaleForDpi Me
Set Win1RT = D2GetRT()
Do
Sleep
Until Me Is Nothing
Sub Win_1_Paint
D2BeginDraw Win1RT
D2Clear D2C_Yellow
D2Text 50, 50, "Move mouse over window"
D2EndDraw
EndSub
Sub Win_1_ReSize
D2ResizeRT Win1RT, _X, _Y
Sub Win_1_MouseMove(Button&, Shift&, x!, y!) ' x,y in ScaleWidth/Height-units
x! = x! * ScaleMX, y! = y! * ScaleMY ' to pixels
D2BeginDraw Win1RT
D2Plot D2PixelsToDIP(x!), D2PixelsToDIP(y!) ' pixels to D2-DIP
D2EndDraw
EndSub
Sub Win_1_MessageProc(hWnd%, Mess%, wParam%, lParam%, retval%, ValidRet?)
Local Int dpi
If Mess% == WM_DPICHANGED
If FormScaleForDpi(Me, wParam%, lParam%) ' scale (resize) form and it's Ocx-es
' Here: Update other Dpi dependent resources (toolbar, bitmaps, Direct2D)
dpi = LoWord(wParam%) ' new Dpi for form
D2SetDpiRT Win1RT, dpi ' update D2 rendertarget's dpi
EndIf
retval% = 0 : ValidRet? = True ' tell OS we handled it
EndIf
EndSub
Function FormScaleForDpi(ByVal frm As Form, Optional newdpi As Int, Optional lParam As Int) As Bool
Local i As Int, c As Control, rc As RECT, prevDpi As Int, newrc As Pointer To RECT, _
tb As Tab, w As Int, h As Int
With frm
' Set initial newdpi for the form and the scale factors for a LoadForm
If .WhatsThisHelpID == 0
If Exist(":{" + .Name) ' a Form-Editor form
.WhatsThisHelpID = WinDpi(0) ' initial dpi is system newdpi
.ScaleWidth = .ScaleWidth * 96 / .WhatsThisHelpID ' set initial scale factors
.ScaleHeight = .ScaleHeight * 96 / .WhatsThisHelpID
Else ' created by OpenW or Form command
.WhatsThisHelpID = 96 ' coord space is 96
EndIf
EndIf
prevDpi = .WhatsThisHelpID
newdpi = LoWord(newdpi)
If newdpi == 0 Then newdpi = WinDpi(.hWnd)
Exit Func If newdpi == prevDpi ' don't continue if equal
' Size the form, except if it is a child window
If !(GetWindowLong(.hWnd, GWL_STYLE) %& WS_CHILD)
If lParam ' size to the OS suggested size
Pointer newrc = lParam ' ptr to RECT in lParam
SizeW .hWnd, newrc.Right - newrc.Left, newrc.Bottom - newrc.Top
Else ' scale based on the current client size
GetClientSize .hWnd, w, h ' can't use _X _Y, they are for ME only
AdjustW .hWnd, Scale(w, newdpi, prevDpi), Scale(h, newdpi, prevDpi)
EndIf
EndIf
.FontSize = .FontSize * newdpi / prevDpi
.ScaleWidth = .ScaleWidth * prevDpi / newdpi
.ScaleHeight = .ScaleHeight * prevDpi / newdpi
' Scale position and size of the Ocx windowed controls
For Each c In frm.Controls
If !(TypeOf(c) Is ImageList || TypeOf(c) Is Timer || _
TypeOf(c) Is CommDlg || TypeOf(c) Is TrayIcon) ' not the windowless OCX-es
' First set fontsize, but not all OCX-es have a Font property
If !(TypeOf(c) Is ProgressBar || TypeOf(c) Is Slider || TypeOf(c) Is Image || TypeOf(c) Is RichEdit)
c.fontsize = c.fontsize * newdpi / prevDpi
ElseIf TypeOf(c) Is RichEdit ' Requires LoadRichEdit50W!
SendMessage c.hwnd, WM_DPICHANGED, MakeLong(newdpi, newdpi), 0
EndIf
' Set new position and size for OCX-controls
GetWinPos(c.hwnd, rc) ' relative to parent
~SetWindowPos(c.hwnd, 0, _
Scale(rc.Left, newdpi, prevDpi), Scale(rc.Top, newdpi, prevDpi), _
Scale(rc.Right - rc.Left, newdpi, prevDpi), _
Scale(rc.Bottom - rc.Top, newdpi, prevDpi), SWP_NOZORDER) ' new pos and size
If TypeOf(c) Is Form ' Scale OCX-es of a child Form Ocx
c.WhatsThisHelpID = prevDpi
~FormScaleForDpi(c, newdpi)
ElseIf TypeOf(c) Is TabStrip ' Scale TabStrip's attached forms
For Each tb In c.Tabs
If TypeOf(tb.Ocx) Is Form
tb.Ocx.WhatsThisHelpID = prevDpi
~FormScaleForDpi(tb.Ocx, newdpi)
EndIf
Next
EndIf
EndIf
Next
.WhatsThisHelpID = newdpi ' store new newdpi
EndWith
FormScaleForDpi = True
EndFunc
By default, D2PixelsToDIP calculates the DIPs for the current render target. The app has to make sure the render target for the window is properly activated (D2GetRT, D2SetRT, or D2BeginDraw). However, if D2PixelsToDIP is executed without setting the current render target, it uses the window's DPI for Me. This is possible because the render target's DPI value is in sync with the window's dpi when the WM_DPICHANGE is properly handled. In a dpi-aware application WM_DPICHANGE is sent when the DPI for the window has changed. The program responds by setting the render target's DPI to the new DPI of the window.
Each time D2PixelsToDIP executes it requests the Dpi values from the render target (D2GetDpiRT) or WindDpi(Me) and uses the Dpi value in the formula: pixels * (Dpi/96). To improve performance the application may keep track of the render target's Dpi itself - using D2GetDpi - and execute the formula directly in the code.
D2GetRT, D2SetRT, D2BeginDraw, D2GetSizeRT, D2AdjustW, D2SetDpiRT
{Created by Sjouke Hamstra; Last updated: 03/03/2022 by James Gaite}