我需要旋转TMetafile图像，至少旋转90度。 通过在位图画布上绘制我的图元文件然后旋转位图很容易旋转它，但我更喜欢将其保持为矢量图像格式。这有可能吗？如果是，那我该怎么做？
答案 0 :(得分：4)
创建第二个图元文件。使用SetWorldTransform创建旋转变换。将第一个图元文件绘制到第二个元文件上，然后让转换完成其余的工作。
答案 1 :(得分：2)
＆＃34; btnRotateClick＆＃34;安德鲁有错误！
我编写了一个更简单的btnRotateClick版本，它可以避免使用div 2舍入错误，但错误仍然存在。
procedure TfrmPreviewImage.RotateMetafile(ClockWise: Boolean);
// Not risolved: Fast increasing rotation time after about 15 rotations.
// Not resolved: Control panel Screen Change dimension of all elements
var
DestMetafile: TMetafile;
DestCanvas: TMetafileCanvas;
TransformMatrix: XFORM;
begin
Assert(Image1.Picture.Graphic is TMetafile);
DestMetafile := TMetafile.Create;
DestMetafile.Enhanced := True;
DestMetafile.SetSize(Image1.Picture.Metafile.Height, Image1.Picture.Metafile.Width);
try
DestCanvas := TMetafileCanvas.Create(DestMetafile, Canvas.Handle);
DestCanvas.Lock;
Try
SetGraphicsMode(DestCanvas.Handle, GM_ADVANCED);
SetMapMode(DestCanvas.Handle, MM_TEXT);
if ClockWise then
begin
Fillchar(TransformMatrix, SizeOf(TransformMatrix), 0);
// Angle := DegToRad(90);
TransformMatrix.eM11 := 0; // Cos(Angle);
TransformMatrix.eM12 := -1; // Sin(Angle);
TransformMatrix.eM21 := 1; // -Sin(Angle);
TransformMatrix.eM22 := 0; // Cos(Angle);
TransformMatrix.eDx := 0;
TransformMatrix.eDy := image1.Picture.Metafile.Width;
end
else
begin
Fillchar(TransformMatrix, SizeOf(TransformMatrix), 0);
// Angle := DegToRad(90);
TransformMatrix.eM11 := 0; // Cos(Angle);
TransformMatrix.eM12 := 1; // Sin(Angle);
TransformMatrix.eM21 := -1; // -Sin(Angle);
TransformMatrix.eM22 := 0; // Cos(Angle);
TransformMatrix.eDx := image1.Picture.Metafile.Height;
TransformMatrix.eDy := 0;
end;
SetWorldTransform(DestCanvas.Handle, TransformMatrix);
DestCanvas.Draw(0, 0, Image1.Picture.Graphic);
Finally
DestCanvas.Unlock;
DestCanvas.Free();
End;
Image1.Picture.Metafile.Assign(DestMetafile);
finally
DestMetafile.Free;
end;
end;
更改全局显示设置的解决方案：
如果用户更改控制面板中的全局显示设置，则为所有组件的像素宽度 在表格上保持不变。但屏幕宽度会发生变化。 我的显示器有1680像素。 更改显示设置后的Screen.Width返回1344像素。 在进行世界转换之前，您需要更正目标图元文件大小。
w1 := MulDiv(w, Screen.Width, ScreenSize.cx);
h1 := MulDiv(h, Screen.Height, ScreenSize.cy);
DestMetafile.SetSize(h1, w1);
经过长时间的搜索才能了解真实的＆＃39;我找到的屏幕尺寸：
const
ENUM_CURRENT_SETTINGS: DWORD = $FFFFFFFF;
EnumDisplaySettings(nil, ENUM_CURRENT_SETTINGS, DevMode);
ScreenSize.cx := DevMode.dmPelsWidth;
在此更正之后，旋转的图像不会改变尺寸。
每次轮换时增加执行时间的解决方案。
我在这里给出一个表来说明问题。
累积旋转会导致执行时间增加。
累积旋转我的意思是旋转已旋转的图像。
ENHMETAHEADER Size
Angle nHandles nRecords (Bytes)
0 4 173 4192
90 7 214 5372
180 10 273 6998
...
450 19 692 20064
540 22 1081 36864
要避免这种情况，请不要旋转已旋转的图像，而是旋转原始图像。
问题的答案取决于您使用SetWorldTransform时编写的程序类型。
另一种方法是更改每个元文件记录的坐标。 Microsoft于2014年发布：[MS-EMF] .pdf：增强的元文件格式。似乎做了很多工作。
还有其他问题。
信息丢失
旋转的Metafile失去了作者和描述。您不能简单地保存此信息 在旋转之前旋转并恢复此信息。属性CreatedBy和Description 是不可写的。 使用：
DestCanvas := TMetafileCanvas.CreateWithComment
另见
单元Winapi.GDIPAPI有关元文件扩展的更多信息。
在线文档EnumDisplaySettings。
<强>说明
将图元文件作为位图旋转会导致质量损失。 我决定复制并粘贴安德鲁的代码，但发现了错误。 我编写了下面的代码，但我的测试可能性很小。我只有一个EMFPLUS文件和 一个监视器。在Windows8.1上测试
这是我的代码：（Delphi XE3）
unit UEmfRotate;
{
Use:
var
FRotationPos : TRotationPosition;
FRotationPos := GetNewPosition(Clockwise, FRotationPos);
UEmfRotate.RotateMetafile(Filename, image1, FRotationPos);
}
interface
uses
System.Types, Vcl.ExtCtrls;
type
TRotationPosition = -3 .. 3;
procedure RotateMetafile(const Path: string; image: TImage;
Position: TRotationPosition);
function GetNewPosition(Clockwise: boolean;
OldPosition: TRotationPosition): TRotationPosition;
implementation
uses
Winapi.Windows, Vcl.Graphics, Vcl.Forms, System.Math;
{
// Resolved: Fast increasing rotation time after about 15 rotations.
// Resolved: Control panel Display Change (dimension of all elements)
// Resolved: Loose of CreatedBy and Description after rotation
}
{
All destination positions from -3 to 3 (-270.. 270)
0 1 2 3
WWW AW AAA WA
AAA AW WWW WA
AW WA
0 -1 -2 -3
WWW WA AAA AW
AAA WA WWW AW
WA AW
}
type
TDestinationArray = array [boolean, TRotationPosition] of TRotationPosition;
TDegrees = array [TRotationPosition] of cardinal;
const // OldPosition -3 -2 -1 0 -1 -2 -3 Clockwise
DestinationArray: TDestinationArray = (( 0, -3, -2, -1, 0, 1, 2), // False
(-2, -1, 0, 1, 2, 3, 0)); // True
// Position -3, -2, -1, 0, 1, 2, 3
Degrees: TDegrees = (90, 180, 270, 0, 90, 180, 270);
function GetNewPosition(Clockwise: boolean;
OldPosition: TRotationPosition): TRotationPosition;
begin
Result := DestinationArray[Clockwise, OldPosition];
end;
function GetDegrees(Position: Integer): cardinal;
begin
Result := Degrees[Position];
end;
function GetScreenSize(out Size: System.Types.TSize): boolean;
// Used to correct for a change in windows global display settings.
const
ENUM_CURRENT_SETTINGS: DWORD = $FFFFFFFF;
var
DevMode: TDevMode;
begin
Size.cx := 0;
Size.cy := 0;
DevMode.dmSize := SizeOf(TDevMode);
Result := EnumDisplaySettings(nil, ENUM_CURRENT_SETTINGS, DevMode);
if Result then
begin
Size.cx := DevMode.dmPelsWidth;
Size.cy := DevMode.dmPelsHeight;
end;
end;
procedure RotateMetafile90(image: TImage);
var
DestMetafile: TMetafile;
DestCanvas: TMetafileCanvas;
TransformMatrix: XFORM;
w, h: Integer;
w1, h1: Integer;
ScreenSize: System.Types.TSize;
begin
w := image.Picture.Width;
h := image.Picture.Height;
// Get screen dimension independent of the control panel display settings.
if GetScreenSize(ScreenSize) then
begin
w1 := MulDiv(w, Screen.Width, ScreenSize.cx);
h1 := MulDiv(h, Screen.Height, ScreenSize.cy);
end
else
begin
// Can not do anything
w1 := w;
h1 := h;
end;
DestMetafile := TMetafile.Create;
DestMetafile.Enhanced := True;
DestMetafile.SetSize(h1, w1);
try
DestCanvas := TMetafileCanvas.CreateWithComment(DestMetafile, 0,
image.Picture.Metafile.CreatedBy, image.Picture.Metafile.Description);
DestCanvas.Lock;
Try
SetGraphicsMode(DestCanvas.Handle, GM_ADVANCED);
SetMapMode(DestCanvas.Handle, MM_TEXT);
Fillchar(TransformMatrix, SizeOf(TransformMatrix), 0);
TransformMatrix.eM11 := 0; // Cos(Angle);
TransformMatrix.eM12 := 1; // Sin(Angle);
TransformMatrix.eM21 := -1; // -Sin(Angle);
TransformMatrix.eM22 := 0; // Cos(Angle);
TransformMatrix.eDx := h;
TransformMatrix.eDy := 0;
SetWorldTransform(DestCanvas.Handle, TransformMatrix);
DestCanvas.Draw(0, 0, image.Picture.Graphic); // Same as Play
Finally
DestCanvas.Unlock;
DestCanvas.Free();
End;
image.Picture := nil;
image.Picture.Metafile.Assign(DestMetafile);
finally
DestMetafile.Free;
end;
end;
procedure RotateMetafile180(image: TImage);
var
DestMetafile: TMetafile;
DestCanvas: TMetafileCanvas;
TransformMatrix: XFORM;
w, h: Integer;
w1, h1: Integer;
ScreenSize: System.Types.TSize;
begin
w := image.Picture.Width;
h := image.Picture.Height;
// Get screen dimension independent of the control panel display settings.
if GetScreenSize(ScreenSize) then
begin
w1 := MulDiv(w, Screen.Width, ScreenSize.cx);
h1 := MulDiv(h, Screen.Height, ScreenSize.cy);
end
else
begin
// Can not do anything
w1 := w;
h1 := h;
end;
DestMetafile := TMetafile.Create;
DestMetafile.Enhanced := True;
DestMetafile.SetSize(w1, h1);
try
DestCanvas := TMetafileCanvas.CreateWithComment(DestMetafile, 0,
image.Picture.Metafile.CreatedBy, image.Picture.Metafile.Description);
DestCanvas.Lock;
Try
SetGraphicsMode(DestCanvas.Handle, GM_ADVANCED);
SetMapMode(DestCanvas.Handle, MM_TEXT);
Fillchar(TransformMatrix, SizeOf(TransformMatrix), 0);
TransformMatrix.eM11 := -1; // Cos(Angle);
TransformMatrix.eM12 := 0; // Sin(Angle);
TransformMatrix.eM21 := 0; // -Sin(Angle);
TransformMatrix.eM22 := -1; // Cos(Angle);
TransformMatrix.eDx := w;
TransformMatrix.eDy := h;
SetWorldTransform(DestCanvas.Handle, TransformMatrix);
DestCanvas.Draw(0, 0, image.Picture.Graphic); // Same as Play
Finally
DestCanvas.Unlock;
DestCanvas.Free();
End;
image.Picture := nil;
image.Picture.Metafile.Assign(DestMetafile);
finally
DestMetafile.Free;
end;
end;
procedure RotateMetafile270(image: TImage);
var
DestMetafile: TMetafile;
DestCanvas: TMetafileCanvas;
TransformMatrix: XFORM;
w, h: Integer;
w1, h1: Integer;
ScreenSize: System.Types.TSize;
begin
w := image.Picture.Width;
h := image.Picture.Height;
// Get screen dimension independent of the control panel display settings.
if GetScreenSize(ScreenSize) then
begin
w1 := MulDiv(w, Screen.Width, ScreenSize.cx);
h1 := MulDiv(h, Screen.Height, ScreenSize.cy);
end
else
begin
// Can not do anything
w1 := w;
h1 := h;
end;
DestMetafile := TMetafile.Create;
DestMetafile.Enhanced := True;
DestMetafile.SetSize(h1, w1);
try
DestCanvas := TMetafileCanvas.CreateWithComment(DestMetafile, 0,
image.Picture.Metafile.CreatedBy, image.Picture.Metafile.Description);
DestCanvas.Lock;
Try
SetGraphicsMode(DestCanvas.Handle, GM_ADVANCED);
SetMapMode(DestCanvas.Handle, MM_TEXT);
Fillchar(TransformMatrix, SizeOf(TransformMatrix), 0);
TransformMatrix.eM11 := 0; // Cos(Angle);
TransformMatrix.eM12 := -1; // Sin(Angle);
TransformMatrix.eM21 := 1; // -Sin(Angle);
TransformMatrix.eM22 := 0; // Cos(Angle);
TransformMatrix.eDx := 0;
TransformMatrix.eDy := w;
SetWorldTransform(DestCanvas.Handle, TransformMatrix);
DestCanvas.Draw(0, 0, image.Picture.Graphic); // Same as Play
Finally
DestCanvas.Unlock;
DestCanvas.Free();
End;
image.Picture := nil;
image.Picture.Metafile.Assign(DestMetafile);
finally
DestMetafile.Free;
end;
end;
procedure RotateMetafile(const Path: string; image: TImage;
Position: TRotationPosition);
{
Cumulative rotating causes increasing execution time
With cumulative rotating i mean rotate an image already rotated
ENHMETAHEADER Size
Angle nHandles nRecords (Bytes)
0 4 173 4192
90 7 214 5372
180 10 273 6998
270 13 354 9352
360 16 479 13212
450 19 692 20064
540 22 1081 36864
To avoid this never rotate an already rotated image, but rotate the
original image.
}
begin
image.Picture.Metafile.LoadFromFile(Path);
Assert(image.Picture.Graphic is TMetafile);
case GetDegrees(Position) of
90:
RotateMetafile90(image);
180:
RotateMetafile180(image);
270:
RotateMetafile270(image);
end;
// image.Picture.SaveToFile('emf.emf');
end;
end.
答案 2 :(得分：0)
工作代码示例，由David的建议制作。每次单击按钮都会将存储在TImage内部的图元文件旋转90度。
procedure TfMain.btnRotateClick(Sender: TObject);
var
SourceMetafile: TMetafile;
DestMetafile: TMetafile;
DestCanvas: TMetafileCanvas;
TransformMatrix: XFORM;
Angle: Double;
begin
Assert(imgRender.Picture.Graphic is TMetafile);
SourceMetafile := imgRender.Picture.Graphic as TMetafile;
DestMetafile := TMetafile.Create();
DestMetafile.Width := SourceMetafile.Height;
DestMetafile.Height := SourceMetafile.Width;
try
DestCanvas := TMetafileCanvas.Create(DestMetafile, Canvas.Handle);
try
SetGraphicsMode(DestCanvas.Handle, GM_ADVANCED);
ZeroMemory(@TransformMatrix, SizeOf(TransformMatrix));
TransformMatrix.eM11 := 1;
TransformMatrix.eM12 := 0;
TransformMatrix.eM21 := 0;
TransformMatrix.eM22 := 1;
TransformMatrix.eDx := -SourceMetafile.Width div 2;
TransformMatrix.eDy := -SourceMetafile.Height div 2;
SetWorldTransform(DestCanvas.Handle, TransformMatrix);
ZeroMemory(@TransformMatrix, SizeOf(TransformMatrix));
Angle := DegToRad(90);
TransformMatrix.eM11 := Cos(Angle);
TransformMatrix.eM12 := Sin(Angle);
TransformMatrix.eM21 := -Sin(Angle);
TransformMatrix.eM22 := Cos(Angle);
TransformMatrix.eDx := 0;
TransformMatrix.eDy := 0;
ModifyWorldTransform(DestCanvas.Handle, TransformMatrix, MWT_RIGHTMULTIPLY);
ZeroMemory(@TransformMatrix, SizeOf(TransformMatrix));
TransformMatrix.eM11 := 1;
TransformMatrix.eM12 := 0;
TransformMatrix.eM21 := 0;
TransformMatrix.eM22 := 1;
TransformMatrix.eDx := SourceMetafile.Height div 2;
TransformMatrix.eDy := SourceMetafile.Width div 2;
ModifyWorldTransform(DestCanvas.Handle, TransformMatrix, MWT_RIGHTMULTIPLY);
DestCanvas.Draw(0, 0, SourceMetafile);
finally
DestCanvas.Free();
end;
imgRender.Picture.Assign(DestMetafile);
finally
DestMetafile.Free();
end;
end;