{
* UPrinterDocPropsDlg.pas
*
* Implements a wrapper for the Windows DocumentProperties dialog box API.
*
* $Rev$
* $Date$
*
* ***** BEGIN LICENSE BLOCK *****
*
* Version: MPL 1.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
* the specific language governing rights and limitations under the License.
*
* The Original Code is UPrinterDocPropsDlg.pas
*
* The Initial Developer of the Original Code is Peter Johnson
* (http://www.delphidabbler.com/).
*
* Portions created by the Initial Developer are Copyright (C) 2007-2009 Peter
* Johnson. All Rights Reserved.
*
* Contributor(s)
* NONE
*
* ***** END LICENSE BLOCK *****
}
unit UPrinterDocPropsDlg;
interface
uses
// Delphi
Windows,
// Project
UExceptions;
type
{
TPrinterDocPropsDlg:
Class that wraps the Windows DocumentProperties dialog box API and
configures, updates and retrieves information from the dialog box.
}
TPrinterDocPropsDlg = class(TObject)
private
fOwnerHandle: HWND;
{Handle of window that owns (parents) the document properties dialog box}
fPrinterHandle: THandle;
{Handle of printer whose document properties are being edited}
fDriverBuf: array[0..255] of Char;
{Stores name of printer driver}
fPortBuf: array[0..255] of Char;
{Stores name of printer port}
fOldPrinterIdx: Integer;
{Index of selected printer when object created: restored on destruction}
function GetPrinterHandle(const PrinterName: string): THandle;
{Gets handle to a named printer.
@param PrinterName [in] Name of printer.
@return Handle to named printer.
@except EPrinterDocPropsDlg raised if we can't get printer handle.
}
procedure GetPrinterInfo(out Device: string; out HDevMode: THandle);
{Retrieves information about the current printer.
@param Device [out] Printer's device name.
@param HDevMode [out] Handle to device specific driver information.
}
procedure SetPrinterInfo(const Device: string; const HDevMode: THandle);
{Sets driver properties of current printer.
@param Device [in] Name of printer device for which properties to be
set. This must be same value returned from GetPrinterInfo.
@param HDevMode [in] Handle to device specific driver information.
}
function SizeOfDeviceMode(const Device: string): Cardinal;
{Gets size of buffer required for a device mode structure.
@param Device [in] Name of device for which structure size is required.
@return Required structure size
}
function AllocDevMode(const Device: string): THandle;
{Allocates storage for a device mode structure.
@param Device [in] Name of device for which structure is required.
}
procedure ReadDocProperties(const Device: string;
const DevMode: PDeviceMode);
{Reads document properties.
@param Device [in] Devide for which document properties required.
@param DevMode [in] Pointer to buffer to receive document properties.
@except EPrinterDocPropsDlg raised if document properties can't be read.
}
function DisplayDialog(const Device: string;
const DevMode: PDeviceMode): Boolean;
{Displays Document Properties dialog box to allow user to modify document
properties.
@param Device [in] Device for which we're are modifying properties.
@param DevMode [in] Pointer to document properties device mode updated
if user OKs dialog. DevMode should be set to values to be displayed in
dialog before calling.
@return True if user OKs dialog and False if user cancels.
}
procedure CopyDeviceMode(const Source: TDeviceMode; out Dest: TDeviceMode);
{Copies a device mode structures. Note that any extended information
appended to the device modes.
@param Source [in] Device mode to be copied.
@param Dest [out] Receives copy of device mode.
}
public
constructor Create(const OwnerHandle: HWND; const PrinterName: string);
{Class constructor. Sets up object.
@param OwnerHandle [in] Handle to window that owns the dialog box.
@param PrinterName [in] Name of printer whose document properties to be
edited.
}
destructor Destroy; override;
{Class destructor. Tears down object and tidies up.
}
function Execute: Boolean;
{Displays dialog box.
@return True if user OKs or False if user Cancels.
}
end;
{
EPrinterDocPropsDlg:
Exception raised by TPrinterDocPropsDlg objects.
}
EPrinterDocPropsDlg = class(ECodeSnip);
implementation
uses
// Delphi
SysUtils, Printers, WinSpool;
resourcestring
// Error messages
sReadWriteError = 'Can''t read or update document properties for device "%s"';
sCantOpenPrinter = 'Can''t open printer "%s"';
sCantFindPrinter = 'Can''t find printer "%s"';
sReadError = 'Can''t read document properties for device "%s"';
{ TPrinterDocPropsDlg }
function TPrinterDocPropsDlg.AllocDevMode(const Device: string): THandle;
{Allocates storage for a device mode structure.
@param Device [in] Name of device for which structure is required.
}
begin
// NOTE: we can't just allocate a TDeviceMode structure since device driver
// may append some custom data to end of structure. SizeOfDeviceMode provides
// required buffer size
Result := GlobalAlloc(GHND, SizeOfDeviceMode(Device));
end;
procedure TPrinterDocPropsDlg.CopyDeviceMode(const Source: TDeviceMode;
out Dest: TDeviceMode);
{Copies a device mode structures. Note that any extended information appended
to the device modes.
@param Source [in] Device mode to be copied.
@param Dest [out] Receives copy of device mode.
}
begin
Move(Source, Dest, SizeOf(TDeviceMode));
end;
constructor TPrinterDocPropsDlg.Create(const OwnerHandle: HWND;
const PrinterName: string);
{Class constructor. Sets up object.
@param OwnerHandle [in] Handle to window that owns the dialog box.
@param PrinterName [in] Name of printer whose document properties to be
edited.
}
var
PrnIdx: Integer; // loops through all printers
Found: Boolean; // flags if printer is found
begin
inherited Create;
fOwnerHandle := OwnerHandle;
fPrinterHandle := GetPrinterHandle(PrinterName);
// Set current printer to one for which properties required, noting current
// one for later restoration
fOldPrinterIdx := -1;
try
fOldPrinterIdx := Printer.PrinterIndex;
except
on EPrinter do {nothing: swallow exception}
end;
Found := False;
try
for PrnIdx := 0 to Pred(Printer.Printers.Count) do
begin
if AnsiSameText(PrinterName, Printer.Printers[PrnIdx]) then
begin
Printer.PrinterIndex := PrnIdx;
Found := True;
Break;
end;
end;
except
on EPrinter do
Found := False;
end;
if not Found then
raise EPrinterDocPropsDlg.CreateFmt(sCantFindPrinter, [PrinterName]);
end;
destructor TPrinterDocPropsDlg.Destroy;
{Class destructor. Tears down object and tidies up.
}
begin
if fPrinterHandle <> 0 then
ClosePrinter(fPrinterHandle);
if fOldPrinterIdx >= 0 then
try
Printer.PrinterIndex := fOldPrinterIdx;
except
on EPrinter do {nothing: swallow exception}
end;
inherited;
end;
function TPrinterDocPropsDlg.DisplayDialog(const Device: string;
const DevMode: PDeviceMode): Boolean;
{Displays Document Properties dialog box to allow user to modify document
properties.
@param Device [in] Device for which we're are modifying properties.
@param DevMode [in] Pointer to document properties device mode updated if
user OKs dialog. DevMode should be set to values to be displayed in
dialog before calling.
@return True if user OKs dialog and False if user cancels.
@except EPrinterDocPropsDlg raised if can't read or write document
properties.
}
const
// Bug error message: ** do not localise
cUnexpectedError = 'TPrinterDocPropsDlg.DisplayDialog: '
+ 'Unexpected return value from DocumentProperties';
var
Res: Integer; // result of calling DocumentProperties API
begin
// Display document properties dialog
// sets DevMode to changed properties if dialog OKd
Res := DocumentProperties(
fOwnerHandle,
fPrinterHandle,
PChar(Device),
DevMode^,
DevMode^,
DM_IN_PROMPT or DM_IN_BUFFER or DM_OUT_BUFFER
);
// Handle result from API call
if Res < 0 then
raise EPrinterDocPropsDlg.CreateFmt(sReadWriteError, [Device]);
case Res of
IDOK: Result := True;
IDCANCEL: Result := False;
else
raise EBug.Create(cUnexpectedError);
end;
end;
function TPrinterDocPropsDlg.Execute: Boolean;
{Displays dialog box.
@return True if user OKs or False if user Cancels.
}
var
Device: string;
HPrnDevMode: THandle; // handle to printer's properties
PPrnDevMode: PDeviceMode; // pointer to printer's properties
HDocDevMode: THandle; // handle to document properties
PDocDevMode: PDeviceMode; // pointer to document properies
begin
// Intialise handles: keeps compiler quiet!
HDocDevMode := 0; //
HPrnDevMode := 0;
try
// Get current printer properties
GetPrinterInfo(Device, HPrnDevMode);
PPrnDevMode := GlobalLock(HPrnDevMode);
// Get current document properties
HDocDevMode := AllocDevMode(Device);
PDocDevMode := GlobalLock(HDocDevMode);
ReadDocProperties(Device, PDocDevMode);
// Update document properties to be same as printer properties
CopyDeviceMode(PPrnDevMode^, PDocDevMode^);
// Display dialog box to allow user to update document properties
Result := DisplayDialog(Device, PDocDevMode);
if Result then
begin
// User OKd
// Update printer properties to be same as updated document properties
CopyDeviceMode(PDocDevMode^, PPrnDevMode^);
SetPrinterInfo(Device, HPrnDevMode);
end;
finally
// Tidy up
if HPrnDevMode <> 0 then
GlobalUnlock(HPrnDevMode);
if HDocDevMode <> 0 then
begin
GlobalUnlock(HDocDevMode);
GlobalFree(HDocDevMode);
end;
end;
end;
function TPrinterDocPropsDlg.GetPrinterHandle(
const PrinterName: string): THandle;
{Gets handle to a named printer.
@param PrinterName [in] Name of printer.
@return Handle to named printer.
@except EPrinterDocPropsDlg raised if we can't get printer handle.
}
begin
if not OpenPrinter(PChar(PrinterName), Result, nil) then
raise EPrinterDocPropsDlg.CreateFmt(sCantOpenPrinter, [PrinterName]);
end;
procedure TPrinterDocPropsDlg.GetPrinterInfo(out Device: string;
out HDevMode: THandle);
{Retrieves information about the current printer.
@param Device [out] Printer's device name.
@param HDevMode [out] Handle to device specific driver information.
}
var
DeviceBuf: array[0..255] of Char; // receives name of device
begin
// Following method gets more info than we need. We store driver and port
// information in fields since we need to pass them to another method later.
// These fields are not used by all versions of Windows and are often empty
// strings.
Printer.GetPrinter(DeviceBuf, fDriverBuf, fPortBuf, HDevMode);
Device := DeviceBuf;
end;
procedure TPrinterDocPropsDlg.ReadDocProperties(const Device: string;
const DevMode: PDeviceMode);
{Reads document properties.
@param Device [in] Devide for which document properties required.
@param DevMode [in] Pointer to buffer to receive document properties.
@except EPrinterDocPropsDlg raised if document properties can't be read.
}
begin
if DocumentProperties(
0, fPrinterHandle, PChar(Device), DevMode^, DevMode^, DM_OUT_BUFFER
) < 0 then
raise EPrinterDocPropsDlg.CreateFmt(sReadError, [Device]);
end;
procedure TPrinterDocPropsDlg.SetPrinterInfo(const Device: string;
const HDevMode: THandle);
{Sets driver properties of current printer.
@param Device [in] Name of printer device for which properties to be set.
This must be same value returned from GetPrinterInfo.
@param HDevMode [in] Handle to device specific driver information.
}
begin
Printer.SetPrinter(PChar(Device), fDriverBuf, fPortBuf, HDevMode);
end;
function TPrinterDocPropsDlg.SizeOfDeviceMode(const Device: string): Cardinal;
{Gets size of buffer required for a device mode structure.
@param Device [in] Name of device for which structure size is required.
@return Required structure size
}
var
DummyDevMode: TDeviceMode; // Unused device mode structure
begin
// We get required size from a special call to DocumentProperties API
// function.
Result := DocumentProperties( // gets size of device mode
0, // no handle => don't display dialog
fPrinterHandle, // handle to printer
PChar(Device), // name of device
DummyDevMode, // unused parameter
DummyDevMode, // unused parameter
0 // informs DocumentProperties we want buffer size
);
end;
end.
