gpt4 book ai didi

delphi - 按真实角度旋转位图

转载 作者:行者123 更新时间:2023-12-03 14:33:01 25 4
gpt4 key购买 nike

从前,阅读this question ,我想知道如何将位图旋转任意角度,而无需自己摆弄所有位。最近,someone else也有明显的困难。

已经有很多关于 90° 间隔旋转的问题,尤其是 this one ,但我想旋转一个真实的角度。最好能够通过旋转来调整图像大小,并为将添加到图像表面的部分设置自定义(透明)背景颜色。然后我认为例程的签名将类似于:

procedure RotateBitmap(Bmp: TBitmap; Angle: Single; AdjustSize: Boolean; 
BackColor: TColor);

These answers提及构建此例程的以下候选者:SetWorldTransform、PlgBlt、GDI+,但我希望看到一个(有效的)实现。

最佳答案

tl;dr; Use GDI+

设置世界变换

使用 WinAPI 的 SetWorldTransform您可以变换设备上下文的空间:旋转、剪切、偏移和缩放。这是通过设置 XFORM 类型的变换矩阵的成员来完成的。根据the documentation填写其成员.

procedure RotateBitmap(Bmp: TBitmap; Rads: Single; AdjustSize: Boolean;
BkColor: TColor = clNone);
var
C: Single;
S: Single;
XForm: tagXFORM;
Tmp: TBitmap;
begin
C := Cos(Rads);
S := Sin(Rads);
XForm.eM11 := C;
XForm.eM12 := S;
XForm.eM21 := -S;
XForm.eM22 := C;
Tmp := TBitmap.Create;
try
Tmp.TransparentColor := Bmp.TransparentColor;
Tmp.TransparentMode := Bmp.TransparentMode;
Tmp.Transparent := Bmp.Transparent;
Tmp.Canvas.Brush.Color := BkColor;
if AdjustSize then
begin
Tmp.Width := Round(Bmp.Width * Abs(C) + Bmp.Height * Abs(S));
Tmp.Height := Round(Bmp.Width * Abs(S) + Bmp.Height * Abs(C));
XForm.eDx := (Tmp.Width - Bmp.Width * C + Bmp.Height * S) / 2;
XForm.eDy := (Tmp.Height - Bmp.Width * S - Bmp.Height * C) / 2;
end
else
begin
Tmp.Width := Bmp.Width;
Tmp.Height := Bmp.Height;
XForm.eDx := (Bmp.Width - Bmp.Width * C + Bmp.Height * S) / 2;
XForm.eDy := (Bmp.Height - Bmp.Width * S - Bmp.Height * C) / 2;
end;
SetGraphicsMode(Tmp.Canvas.Handle, GM_ADVANCED);
SetWorldTransform(Tmp.Canvas.Handle, XForm);
BitBlt(Tmp.Canvas.Handle, 0, 0, Tmp.Width, Tmp.Height, Bmp.Canvas.Handle,
0, 0, SRCCOPY);
Bmp.Assign(Tmp);
finally
Tmp.Free;
end;
end;

PlgBlt

PlgBlt函数执行从源设备上下文中指定的矩形到目标设备上下文中指定的平行四边形的位 block 传输。通过 lpPoint 参数映射源图像的角点。

procedure RotateBitmap(Bmp: TBitmap; Rads: Single; AdjustSize: Boolean;
BkColor: TColor = clNone);
var
C: Single;
S: Single;
Tmp: TBitmap;
OffsetX: Single;
OffsetY: Single;
Points: array[0..2] of TPoint;
begin
C := Cos(Rads);
S := Sin(Rads);
Tmp := TBitmap.Create;
try
Tmp.TransparentColor := Bmp.TransparentColor;
Tmp.TransparentMode := Bmp.TransparentMode;
Tmp.Transparent := Bmp.Transparent;
Tmp.Canvas.Brush.Color := BkColor;
if AdjustSize then
begin
Tmp.Width := Round(Bmp.Width * Abs(C) + Bmp.Height * Abs(S));
Tmp.Height := Round(Bmp.Width * Abs(S) + Bmp.Height * Abs(C));
OffsetX := (Tmp.Width - Bmp.Width * C + Bmp.Height * S) / 2;
OffsetY := (Tmp.Height - Bmp.Width * S - Bmp.Height * C) / 2;
end
else
begin
Tmp.Width := Bmp.Width;
Tmp.Height := Bmp.Height;
OffsetX := (Bmp.Width - Bmp.Width * C + Bmp.Height * S) / 2;
OffsetY := (Bmp.Height - Bmp.Width * S - Bmp.Height * C) / 2;
end;
Points[0].X := Round(OffsetX);
Points[0].Y := Round(OffsetY);
Points[1].X := Round(OffsetX + Bmp.Width * C);
Points[1].Y := Round(OffsetY + Bmp.Width * S);
Points[2].X := Round(OffsetX - Bmp.Height * S);
Points[2].Y := Round(OffsetY + Bmp.Height * C);
PlgBlt(Tmp.Canvas.Handle, Points, Bmp.Canvas.Handle, 0, 0, Bmp.Width,
Bmp.Height, 0, 0, 0);
Bmp.Assign(Tmp);
finally
Tmp.Free;
end;
end;

图形32

Graphics32是一个专门为快速位图处理而设计的库。它需要一些经验才能充分发挥其潜力,但是the documentation以及提供的示例应该可以帮助您入门。

TBitmap32 图像的旋转是通过使用许多可用的变换类之一对其进行变换来完成的。这里需要 TAffineTransformation 类。首先,将图像大小的一半移动到左上角,然后旋转,并将结果移回到右下角,可能使用新的图像尺寸。

uses
GR32, GR32_Transforms;

procedure RotateBitmap(Bmp: TBitmap32; Degs: Integer; AdjustSize: Boolean;
BkColor: TColor = clNone; Transparent: Boolean = False); overload;
var
Tmp: TBitmap32;
Transformation: TAffineTransformation;
begin
Tmp := TBitmap32.Create;
Transformation := TAffineTransformation.Create;
try
Transformation.BeginUpdate;
Transformation.SrcRect := FloatRect(0, 0, Bmp.Width, Bmp.Height);
Transformation.Translate(-0.5 * Bmp.Width, -0.5 * Bmp.Height);
Transformation.Rotate(0, 0, -Degs);
if AdjustSize then
with Transformation.GetTransformedBounds do
Tmp.SetSize(Round(Right - Left), Round(Bottom - Top))
else
Tmp.SetSize(Bmp.Width, Bmp.Height);
Transformation.Translate(0.5 * Tmp.Width, 0.5 * Tmp.Height);
Transformation.EndUpdate;
Tmp.Clear(Color32(BkColor));
if not Transparent then
Bmp.DrawMode := dmTransparent;
Transform(Tmp, Bmp, Transformation);
Bmp.Assign(Tmp);
Bmp.OuterColor := Color32(BkColor);
if Transparent then
Bmp.DrawMode := dmTransparent;
finally
Transformation.Free;
Tmp.Free;
end;
end;

procedure RotateBitmap(Bmp: TBitmap; Degs: Integer; AdjustSize: Boolean;
BkColor: TColor = clNone); overload;
var
Tmp: TBitmap32;
Transparent: Boolean;
begin
Tmp := TBitmap32.Create;
try
Transparent := Bmp.Transparent;
Tmp.Assign(Bmp);
RotateBitmapGR32(Tmp, Degs, AdjustSize, BkColor, Transparent);
Bmp.Assign(Tmp);
if Transparent then
Bmp.Transparent := True;
finally
Tmp.Free;
end;
end;

GDI+

在 Microsoft 的 Windows XP 中引入 GDI+ API 比默认的 GDI API 更高效。对于 Delphi 2009 及更高版本,该库可用 from here 。对于较旧的 Delphi 版本,该库可用 from here .

在 GDI+ 中,旋转也是通过变换矩阵完成的。但绘画的工作方式却截然不同。创建一个 TGPGraphics 对象并使用其构造函数将其附加到设备上下文。随后,对象上的绘制操作由 API 进行翻译,并将输出到目标上下文。

uses
GDIPOBJ, GDIPAPI; // < D2009
GdiPlus; // >= D2009

procedure RotateBitmap(Bmp: TBitmap; Degs: Integer; AdjustSize: Boolean;
BkColor: TColor = clNone);
var
Tmp: TGPBitmap;
Matrix: TGPMatrix;
C: Single;
S: Single;
NewSize: TSize;
Graphs: TGPGraphics;
P: TGPPointF;
begin
Tmp := TGPBitmap.Create(Bmp.Handle, Bmp.Palette);
Matrix := TGPMatrix.Create;
try
Matrix.RotateAt(Degs, MakePoint(0.5 * Bmp.Width, 0.5 * Bmp.Height));
if AdjustSize then
begin
C := Cos(DegToRad(Degs));
S := Sin(DegToRad(Degs));
NewSize.cx := Round(Bmp.Width * Abs(C) + Bmp.Height * Abs(S));
NewSize.cy := Round(Bmp.Width * Abs(S) + Bmp.Height * Abs(C));
Bmp.Width := NewSize.cx;
Bmp.Height := NewSize.cy;
end;
Graphs := TGPGraphics.Create(Bmp.Canvas.Handle);
try
Graphs.Clear(ColorRefToARGB(ColorToRGB(BkColor)));
Graphs.SetTransform(Matrix);
Graphs.DrawImage(Tmp, (Cardinal(Bmp.Width) - Tmp.GetWidth) div 2,
(Cardinal(Bmp.Height) - Tmp.GetHeight) div 2);
finally
Graphs.Free;
end;
finally
Matrix.Free;
Tmp.Free;
end;
end;

处理透明度

上面的例程保留了 feed 位图的透明设置,但 Graphics32 解决方案除外,它需要额外的 Transparent 参数。

性能和图像质量

我编写了一个测试应用程序(请参阅下面的完整代码)来调整各种方法的性能并比较生成的图像质量。

第一个也是最重要的结论是,GDI+ 使用抗锯齿技术,而其他技术则没有,从而产生最佳的图像质量。 (我尝试通过设置 CompositingQualityInterpolationModeSmoothingModePixelOffsetMode 来防止抗锯齿,但没有成功,所以当抗锯齿不是首选,不要使用 GDI+。)

此外,GDI+ 解决方案也是迄今为止最快的方法。

Test results

unit RotateTestForm;

interface

uses
Windows, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, ExtCtrls,
JPEG, Math, GR32, GR32_Transforms, GDIPOBJ, GDIPAPI {, GdiPlus};

type
TTestForm = class(TForm)
private
FImage: TImage;
FOpenDialog: TOpenDialog;
procedure FormPaint(Sender: TObject);
public
constructor Create(AOwner: TComponent); override;
end;

var
TestForm: TTestForm;

implementation

{$R *.dfm}

procedure RotateBitmapSWT(Bmp: TBitmap; Rads: Single; AdjustSize: Boolean;
BkColor: TColor = clNone);
var
C: Single;
S: Single;
XForm: TXForm;
Tmp: TBitmap;
begin
C := Cos(Rads);
S := Sin(Rads);
XForm.eM11 := C;
XForm.eM12 := S;
XForm.eM21 := -S;
XForm.eM22 := C;
Tmp := TBitmap.Create;
try
Tmp.TransparentColor := Bmp.TransparentColor;
Tmp.TransparentMode := Bmp.TransparentMode;
Tmp.Transparent := Bmp.Transparent;
Tmp.Canvas.Brush.Color := BkColor;
if AdjustSize then
begin
Tmp.Width := Round(Bmp.Width * Abs(C) + Bmp.Height * Abs(S));
Tmp.Height := Round(Bmp.Width * Abs(S) + Bmp.Height * Abs(C));
XForm.eDx := (Tmp.Width - Bmp.Width * C + Bmp.Height * S) / 2;
XForm.eDy := (Tmp.Height - Bmp.Width * S - Bmp.Height * C) / 2;
end
else
begin
Tmp.Width := Bmp.Width;
Tmp.Height := Bmp.Height;
XForm.eDx := (Bmp.Width - Bmp.Width * C + Bmp.Height * S) / 2;
XForm.eDy := (Bmp.Height - Bmp.Width * S - Bmp.Height * C) / 2;
end;
SetGraphicsMode(Tmp.Canvas.Handle, GM_ADVANCED);
SetWorldTransform(Tmp.Canvas.Handle, XForm);
BitBlt(Tmp.Canvas.Handle, 0, 0, Tmp.Width, Tmp.Height, Bmp.Canvas.Handle,
0, 0, SRCCOPY);
Bmp.Assign(Tmp);
finally
Tmp.Free;
end;
end;

procedure RotateBitmapPLG(Bmp: TBitmap; Rads: Single; AdjustSize: Boolean;
BkColor: TColor = clNone);
var
C: Single;
S: Single;
Tmp: TBitmap;
OffsetX: Single;
OffsetY: Single;
Points: array[0..2] of TPoint;
begin
C := Cos(Rads);
S := Sin(Rads);
Tmp := TBitmap.Create;
try
Tmp.TransparentColor := Bmp.TransparentColor;
Tmp.TransparentMode := Bmp.TransparentMode;
Tmp.Transparent := Bmp.Transparent;
Tmp.Canvas.Brush.Color := BkColor;
if AdjustSize then
begin
Tmp.Width := Round(Bmp.Width * Abs(C) + Bmp.Height * Abs(S));
Tmp.Height := Round(Bmp.Width * Abs(S) + Bmp.Height * Abs(C));
OffsetX := (Tmp.Width - Bmp.Width * C + Bmp.Height * S) / 2;
OffsetY := (Tmp.Height - Bmp.Width * S - Bmp.Height * C) / 2;
end
else
begin
Tmp.Width := Bmp.Width;
Tmp.Height := Bmp.Height;
OffsetX := (Bmp.Width - Bmp.Width * C + Bmp.Height * S) / 2;
OffsetY := (Bmp.Height - Bmp.Width * S - Bmp.Height * C) / 2;
end;
Points[0].X := Round(OffsetX);
Points[0].Y := Round(OffsetY);
Points[1].X := Round(OffsetX + Bmp.Width * C);
Points[1].Y := Round(OffsetY + Bmp.Width * S);
Points[2].X := Round(OffsetX - Bmp.Height * S);
Points[2].Y := Round(OffsetY + Bmp.Height * C);
PlgBlt(Tmp.Canvas.Handle, Points, Bmp.Canvas.Handle, 0, 0, Bmp.Width,
Bmp.Height, 0, 0, 0);
Bmp.Assign(Tmp);
finally
Tmp.Free;
end;
end;

procedure RotateBitmapGR32(Bmp: TBitmap32; Degs: Integer; AdjustSize: Boolean;
BkColor: TColor = clNone; Transparent: Boolean = False); overload;
var
Tmp: TBitmap32;
Transformation: TAffineTransformation;
begin
Tmp := TBitmap32.Create;
Transformation := TAffineTransformation.Create;
try
Transformation.BeginUpdate;
Transformation.SrcRect := FloatRect(0, 0, Bmp.Width, Bmp.Height);
Transformation.Translate(-0.5 * Bmp.Width, -0.5 * Bmp.Height);
Transformation.Rotate(0, 0, -Degs);
if AdjustSize then
with Transformation.GetTransformedBounds do
Tmp.SetSize(Round(Right - Left), Round(Bottom - Top))
else
Tmp.SetSize(Bmp.Width, Bmp.Height);
Transformation.Translate(0.5 * Tmp.Width, 0.5 * Tmp.Height);
Transformation.EndUpdate;
Tmp.Clear(Color32(BkColor));
if not Transparent then
Bmp.DrawMode := dmTransparent;
Transform(Tmp, Bmp, Transformation);
Bmp.Assign(Tmp);
Bmp.OuterColor := Color32(BkColor);
if Transparent then
Bmp.DrawMode := dmTransparent;
finally
Transformation.Free;
Tmp.Free;
end;
end;

procedure RotateBitmapGR32(Bmp: TBitmap; Degs: Integer; AdjustSize: Boolean;
BkColor: TColor = clNone); overload;
var
Tmp: TBitmap32;
Transparent: Boolean;
begin
Tmp := TBitmap32.Create;
try
Transparent := Bmp.Transparent;
Tmp.Assign(Bmp);
RotateBitmapGR32(Tmp, Degs, AdjustSize, BkColor, Transparent);
Bmp.Assign(Tmp);
if Transparent then
Bmp.Transparent := True;
finally
Tmp.Free;
end;
end;

procedure RotateBitmapGDIP(Bmp: TBitmap; Degs: Integer; AdjustSize: Boolean;
BkColor: TColor = clNone);
var
Tmp: TGPBitmap;
Matrix: TGPMatrix;
C: Single;
S: Single;
NewSize: TSize;
Graphs: TGPGraphics;
P: TGPPointF;
begin
Tmp := TGPBitmap.Create(Bmp.Handle, Bmp.Palette);
Matrix := TGPMatrix.Create;
try
Matrix.RotateAt(Degs, MakePoint(0.5 * Bmp.Width, 0.5 * Bmp.Height));
if AdjustSize then
begin
C := Cos(DegToRad(Degs));
S := Sin(DegToRad(Degs));
NewSize.cx := Round(Bmp.Width * Abs(C) + Bmp.Height * Abs(S));
NewSize.cy := Round(Bmp.Width * Abs(S) + Bmp.Height * Abs(C));
Bmp.Width := NewSize.cx;
Bmp.Height := NewSize.cy;
end;
Graphs := TGPGraphics.Create(Bmp.Canvas.Handle);
try
Graphs.Clear(ColorRefToARGB(ColorToRGB(BkColor)));
Graphs.SetTransform(Matrix);
Graphs.DrawImage(Tmp, (Cardinal(Bmp.Width) - Tmp.GetWidth) div 2,
(Cardinal(Bmp.Height) - Tmp.GetHeight) div 2);
finally
Graphs.Free;
end;
finally
Matrix.Free;
Tmp.Free;
end;
end;

{ TTestForm }

constructor TTestForm.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
Font.Name := 'Tahoma';
Top := 0;
ClientWidth := 560;
ClientHeight := 915;
Show;
FImage := TImage.Create(Self);
FOpenDialog := TOpenDialog.Create(Self);
FOpenDialog.Title := 'Select an small sized image (min. 100 x 100)';
FOpenDialog.Options := FOpenDialog.Options + [ofFileMustExist];
FOpenDialog.Filter := 'JPEG|*.JPG|BMP|*.BMP';
if FOpenDialog.Execute then
begin
FImage.Picture.LoadFromFile(FOpenDialog.FileName);
OnPaint := FormPaint;
Invalidate;
end
else
Application.Terminate;
end;

procedure TTestForm.FormPaint(Sender: TObject);
var
Img: TBitmap;
Bmp: TBitmap;
Bmp32: TBitmap32;
BkColor: TColor;
AdjustSize: Boolean;
Degs: Integer;
Rads: Single;
RotCount: Integer;
I: Integer;
Tick: Cardinal;
begin
Img := TBitmap.Create;
Bmp := TBitmap.Create;
Bmp32 := TBitmap32.Create;
try
BkColor := clBtnFace;
Img.Canvas.Brush.Color := BkColor;
Img.Width := 100;
Img.Height := 100;
Img.Canvas.Draw(0, 0, FImage.Picture.Graphic);
AdjustSize := False;
Degs := 45;
Rads := DegToRad(Degs);
RotCount := 1000;

Canvas.TextOut(10, 10, 'Original:');
Canvas.Draw(10, 30, Img);
Canvas.TextOut(10, 140, Format('Size = %d x %d', [Img.Width, Img.Height]));
Canvas.TextOut(10, 160, Format('Angle = %d°', [Degs]));
Canvas.TextOut(10, 250, Format('%d rotations:', [RotCount]));

Canvas.TextOut(120, 10, 'SetWorldTransform:');
Bmp.Assign(Img);
RotateBitmapSWT(Bmp, Rads, AdjustSize, BkColor);
Canvas.Draw(120, 30, Bmp);
if not AdjustSize then
begin
Tick := GetTickCount;
for I := 0 to RotCount - 2 do
RotateBitmapSWT(Bmp, Rads, AdjustSize, BkColor);
Canvas.TextOut(120, 250, Format('%d msec', [GetTickCount - Tick]));
Canvas.Draw(120, 140, Bmp);
end;

Canvas.TextOut(230, 10, 'PlgBlt:');
Bmp.Assign(Img);
RotateBitmapPLG(Bmp, Rads, AdjustSize, BkColor);
Canvas.Draw(230, 30, Bmp);
if not AdjustSize then
begin
Tick := GetTickCount;
for I := 0 to RotCount - 2 do
RotateBitmapPLG(Bmp, Rads, AdjustSize, BkColor);
Canvas.TextOut(230, 250, Format('%d msec', [GetTickCount - Tick]));
Canvas.Draw(230, 140, Bmp);
end;

Canvas.TextOut(340, 10, 'Graphics32:');
Bmp.Assign(Img);
RotateBitmapGR32(Bmp, Degs, AdjustSize, BkColor);
Canvas.Draw(340, 30, Bmp);
if not AdjustSize then
begin
Tick := GetTickCount;
for I := 0 to RotCount - 2 do
RotateBitmapGR32(Bmp, Degs, AdjustSize, BkColor);
Canvas.TextOut(340, 250, Format('%d msec', [GetTickCount - Tick]));
Canvas.Draw(340, 140, Bmp);

// Without in between conversion to TBitmap:
Bmp32.Assign(Img);
Tick := GetTickCount;
for I := 0 to RotCount - 1 do
RotateBitmapGR32(Bmp32, Degs, AdjustSize, BkColor, False);
Canvas.TextOut(340, 270, Format('%d msec (optimized)',
[GetTickCount - Tick]));
end;

Canvas.TextOut(450, 10, 'GDI+ :');
Bmp.Assign(Img);
RotateBitmapGDIP(Bmp, Degs, AdjustSize, BkColor);
Canvas.Draw(450, 30, Bmp);
if not AdjustSize then
begin
Tick := GetTickCount;
for I := 0 to RotCount - 2 do
RotateBitmapGDIP(Bmp, Degs, AdjustSize, BkColor);
Canvas.TextOut(450, 250, Format('%d msec', [GetTickCount - Tick]));
Canvas.Draw(450, 140, Bmp);
end;
finally
Bmp32.Free;
Bmp.Free;
Img.Free;
OnPaint := nil;
end;
end;

end.

关于delphi - 按真实角度旋转位图,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/10633400/

25 4 0
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com