delphi – 以实角旋转位图

Delphi 前端之家
前端之家收集整理的这篇文章主要介绍了delphi – 以实角旋转位图，前端之家小编觉得挺不错的，现在分享给大家，也给大家做个参考。
曾经读过 this question的时候，我想知道如何在任何程度上旋转位图，而不用自己摆放所有的位。最近 someone else也有明显的困难。

已经有许多问题处理90°间隔的旋转，大多数不合适this one，但是我想要旋转一个真正的角度。最好有可能由于旋转而调整图像尺寸，并为要添加到图像表面的部件设置自定义(透明)背景颜色。那么我假设例程的签名看起来像：

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

These answers提到以下候选人构建这个例程：SetWorldTransform，PlgBlt，GDI，但我想看到(高效)的实现。

解决方法

tl;dr; Use GDI+

SetWorldTransform

使用WinAPI的SetWorldTransform，您可以转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完成的。按照the documentation填写会员。

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,Tmp.Width,Tmp.Height,Bmp.Canvas.Handle,SRCCOPY);
    Bmp.Assign(Tmp);
  finally
    Tmp.Free;
  end;
end;

PlgBlt

PlgBlt功能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块传输。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.Width,Bmp.Height,0);
    Bmp.Assign(Tmp);
  finally
    Tmp.Free;
  end;
end;

Graphics32

Graphics32是专门用于快速位图处理的库。它需要一些经验来掌握其全部潜力，但the documentation以及所提供的示例应该让您开始。

TBitmap32图像的旋转是通过将许多可用的转换类之一进行转换来完成的。在这里需要TAffineTransformation类。首先，将图像的一半大小移动到左上角，然后旋转，然后将结果移回右下角，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,Bmp.Height);
    Transformation.Translate(-0.5 * Bmp.Width,-0.5 * Bmp.Height);
    Transformation.Rotate(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Windows XP中引入，Microsoft的GDI+ API比默认的GDI API更有效率。对于Delphi 2009及以上版本，库可用from here.对于较旧的Delphi版本，库可用from here。

在GDI中，旋转也由变换矩阵完成。绘画的作品有很大的不同。创建TGPGraphics对象并将其附加到其构造函数的设备上下文中。随后，通过API翻译对象的绘制操作，并将其输出到目标上下文。

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

上面的例程保存了fead位图的透明设置，但需要一个额外的Transparent参数的Graphics32解决方案除外。

性能和图像质量

我写了一个测试应用程序(见下面的完整代码)来调整各种方法的性能，并比较所得到的图像质量。

第一个也是最重要的结论是，GDI使用反锯齿，其他的没有别的，导致最好的图像质量。 (我没有成功尝试通过设置CompositingQuality，InterpolationMode，SmoothingMode和PixelOffsetMode来防止抗锯齿，所以当不使用别名时不要使用GDI。)

此外，GDI解决方案也是迄今为止最快的方法。

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

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

    Canvas.TextOut(340,'Graphics32:');
    Bmp.Assign(Img);
    RotateBitmapGR32(Bmp,BkColor);
    Canvas.Draw(340,Bmp);
    if not AdjustSize then
    begin
      Tick := GetTickCount;
      for I := 0 to RotCount - 2 do
        RotateBitmapGR32(Bmp,BkColor);
      Canvas.TextOut(340,[GetTickCount - Tick]));
      Canvas.Draw(340,Bmp);

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

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

end.
原文链接：https://www.f2er.com/delphi/103574.html

猜你在找的Delphi相关文章

ffmpeg 部分api delphi 版
ffmpeg 是一套强大的开源的多媒体库 一般都是用 c/c++ 调用， 抽空研究了一下该库...
寄存器备忘
32位CPU所含有的寄存器有：4个数据寄存器(EAX、EBX、ECX和EDX)2个变址和指针寄存器(ESI和E...
键位码
指令整理
1 mov dst, src dst是目的操作数，src是源操作数，指令实现的功能是：将源操作数送到目的操...
delphi中ShellExecute使用详解
有三个API函数可以运行可执行文件WinExec、ShellExecute和CreateProcess。 1.CreateProces...
delphi控件安装与删除
附带通用控件安装方法： ---------- 基本安装 1、对于单个控件，Componet-->install co...
Delphi 怎样 把TParams 或 record写到流里面
type   TRec=Record     msg:string;     pic:TMemoryStream; end; procedure TForm2...
一个用delphi写的整合汇编与api的简单的窗口程序
program Project1; { Types and Structures Definition } type   WNDCLASSEX = packed re...
用Delphi模拟键盘输入
   在Windows大行其道的今天，windows界面程序受到广大用户的欢迎。对这些程序的操作不...
Delphi 中的 procedure of object
delphi中经常见到以下两种定义 Type TMouseProc = procedure (X,Y:integer); TMouse...
PHPJavaJava SEPythonC#C&C++RubyVBasp.NetGoPerlnettyDjangoDelphiJsp.NET CoreSpringFlaskSpringbootSpringMVCLuaLaravelMybatisAspGroovyThinkPHPYiiswoole
文件时间pythonm相等性PHP Warning时间问题问题解决pcntl_signal采样点wav模块动态文本调用频率限制对外暴露多个访问请求更新数据表模型结构type()方法比较速度手写体sobel算子保存模型Image类nn.Conv2dpytorch1.0kaggleDCGAN交并比range()用法打印模型反卷积卷积