GdiPlus[52]: 图像(四) 图像信息

相关属性、方法、函数:

---

IGPImage.Width;                { 宽度(单位是像素) }

IGPImage.Height;               { 高度(单位是像素) }

IGPImage.HorizontalResolution; { 获取水平分辨率(以"像素/英寸"为单位) }

IGPImage.VerticalResolution;   { 获取垂直分辨率(以"像素/英寸"为单位) }

IGPImage.RawFormat;            { 获取图像的文件格式 }

IGPImage.PixelFormat;          { 获取图像的像素格式 }

IGPImage.Flags;                { 获取图像像素的属性标志 }

IGPImage.ImageType;            { 图像类型(Bitmap/Metafile/Unknown) }

IGPImage.Palette;              { 获取或设置调色板 }



IGPImage.GetFrameCount(); { 获取帧数 }



function GetPixelFormatSize();     { 返回指定像素格式的颜色深度(每个像素的位数) }

function IsIndexedPixelFormat();   { 判断像素格式是否是索引的 }

function IsAlphaPixelFormat();     { 判断像素格式是否包含 alpha 信息 }

function IsCanonicalPixelFormat(); { 像素格式是否是每个像素 32 位(标准) }

function IsExtendedPixelFormat();  { 像素格式是否是每个像素 64 位 }


 
   

尺寸与分辨率:

---

uses GdiPlus;



procedure TForm1.FormPaint(Sender: TObject);

var

  Graphics: IGPGraphics;

  Image: IGPImage;

  Size: TGPSizeF;

  Rect: TGPRectF;

  SrcUnit: TGPUnit;

  dx,dy: Single;

begin

  Image := TGPImage.Create('C:\GdiPlusImg\Apple.gif');

  Graphics := TGPGraphics.Create(Handle);

  Graphics.DrawImage(Image, 10, 10);



  ShowMessageFmt('Width:%d, Height:%d', [Image.Width, Image.Height]);

  { Width:120, Height:128 }

  

  Image.GetPhysicalDimension(Size);

  ShowMessageFmt('Width:%f, Height:%f', [Size.Width, Size.Height]);

  { Width:120.00, Height:128.00 }



  Image.GetBounds(Rect, SrcUnit); 

  ShowMessageFmt('Width:%f, Height: %f; 单位: %d', [Size.Width, Size.Height, Ord(SrcUnit)]);

  { Width:120.00, Height:128.00; 单位: 2 } //TGPUnit(2) = UnitPixel;



  dx := Image.HorizontalResolution;

  dy := Image.VerticalResolution;

  ShowMessageFmt('水平分辨率: %f, 垂直分辨率: %f', [dx, dy]);

  { 水平分辨率: 96.00, 垂直分辨率: 96.00 }

end;


 
   

文件格式:

---

uses GdiPlus;



procedure TForm1.Button1Click(Sender: TObject);

var

  Image: IGPImage;

  f: string;

begin

  Image := TGPImage.Create('C:\GdiPlusImg\Bird.bmp');



  if IsEqualGUID(Image.RawFormat, ImageFormatUndefined) then f := 'Undefined';

  if IsEqualGUID(Image.RawFormat, ImageFormatMemoryBMP) then f := 'MemoryBMP';

  if IsEqualGUID(Image.RawFormat, ImageFormatBMP)       then f := 'BMP';

  if IsEqualGUID(Image.RawFormat, ImageFormatEMF)       then f := 'EMF';

  if IsEqualGUID(Image.RawFormat, ImageFormatWMF)       then f := 'WMF';

  if IsEqualGUID(Image.RawFormat, ImageFormatJPEG)      then f := 'JPEG';

  if IsEqualGUID(Image.RawFormat, ImageFormatPNG)       then f := 'PNG';

  if IsEqualGUID(Image.RawFormat, ImageFormatGIF)       then f := 'GIF';

  if IsEqualGUID(Image.RawFormat, ImageFormatTIFF)      then f := 'TIFF';

  if IsEqualGUID(Image.RawFormat, ImageFormatEXIF)      then f := 'EXIF';

  if IsEqualGUID(Image.RawFormat, ImageFormatIcon)      then f := 'Icon';



  ShowMessage(f); { BMP }

end;


 
   

像素格式:

---

uses GdiPlus;



procedure TForm1.Button1Click(Sender: TObject);

var

  Image: IGPImage;

  pf: string;

begin

  Image := TGPImage.Create('C:\GdiPlusImg\Bird.bmp');



  case Image.PixelFormat of

    PixelFormat1bppIndexed    : pf := 'PixelFormat1bppIndexed';

    PixelFormat4bppIndexed    : pf := 'PixelFormat4bppIndexed';

    PixelFormat8bppIndexed    : pf := 'PixelFormat8bppIndexed';

    PixelFormat16bppGrayScale : pf := 'PixelFormat16bppGrayScale';

    PixelFormat16bppRGB555    : pf := 'PixelFormat16bppRGB555';

    PixelFormat16bppRGB565    : pf := 'PixelFormat16bppRGB565';

    PixelFormat16bppARGB1555  : pf := 'PixelFormat16bppARGB1555 ';

    PixelFormat24bppRGB       : pf := 'PixelFormat24bppRGB';

    PixelFormat32bppRGB       : pf := 'PixelFormat32bppRGB';

    PixelFormat32bppARGB      : pf := 'PixelFormat32bppARGB';

    PixelFormat32bppPARGB     : pf := 'PixelFormat32bppPARGB';

    PixelFormat48bppRGB       : pf := 'PixelFormat48bppRGB';

    PixelFormat64bppARGB      : pf := 'PixelFormat64bppARGB';

    PixelFormat64bppPARGB     : pf := 'PixelFormat64bppPARGB';

  end;



  ShowMessage(pf); { PixelFormat8bppIndexed }

end;


 
   

像素属性:

---

uses GdiPlus;



procedure TForm1.Button1Click(Sender: TObject);

const

  n = sLineBreak;

var

  Image: IGPImage;

  f: TGPImageFlags;

  s: string;

begin

  Image := TGPImage.Create('C:\GdiPlusImg\Bird.bmp');

  f := Image.Flags;



  if TGPImageFlag(0)  in f then s := s + 'ImageFlagsScalable'          + n;

  if TGPImageFlag(1)  in f then s := s + 'ImageFlagsHasAlpha'          + n;

  if TGPImageFlag(2)  in f then s := s + 'ImageFlagsHasTranslucent'    + n;

  if TGPImageFlag(3)  in f then s := s + 'ImageFlagsPartiallyScalable' + n;

  if TGPImageFlag(4)  in f then s := s + 'ImageFlagsColorSpaceRGB'     + n;

  if TGPImageFlag(5)  in f then s := s + 'ImageFlagsColorSpaceCMYK'    + n;

  if TGPImageFlag(6)  in f then s := s + 'ImageFlagsColorSpaceGRAY'    + n;

  if TGPImageFlag(7)  in f then s := s + 'ImageFlagsColorSpaceYCBCR'   + n;

  if TGPImageFlag(8)  in f then s := s + 'ImageFlagsColorSpaceYCCK'    + n;

  if TGPImageFlag(12) in f then s := s + 'ImageFlagsHasRealDPI'        + n;

  if TGPImageFlag(13) in f then s := s + 'ImageFlagsHasRealPixelSize'  + n;

  if TGPImageFlag(16) in f then s := s + 'ImageFlagsReadOnly'          + n;

  if TGPImageFlag(17) in f then s := s + 'ImageFlagsCaching'           + n;



  ShowMessage(s);

  { ImageFlagsColorSpaceRGB / ImageFlagsHasRealPixelSize / ImageFlagsReadOnly }

end;


 
   

图像类型:

---

uses GdiPlus;



procedure TForm1.Button1Click(Sender: TObject);

var

  Image: IGPImage;

  str: string;

begin

  ChDir('C:\GdiPlusImg\');

  Image := TGPImage.Create('SampleMetafile.emf');



  case Image.ImageType of

    ImageTypeUnknown : str := 'Unknown';

    ImageTypeBitmap  : str := 'Bitmap';

    ImageTypeMetafile: str := 'Metafile';

  end;

  ShowMessage(str); { Metafile }

end;


 
   

几个图像相关的全局函数:

---

uses GdiPlus;



procedure TForm1.Button1Click(Sender: TObject);

var

  Image: IGPImage;

  n: Integer;

  b: Boolean;

begin

  Image := TGPImage.Create('C:\GdiPlusImg\Grapes.jpg');



  { 每个像素的大小 }

  n := GetPixelFormatSize(Image.PixelFormat);

  ShowMessage(IntToStr(n)); { 24 }



  { 是否使用了索引色 }

  b := IsIndexedPixelFormat(Image.PixelFormat);

  ShowMessage(BoolToStr(b, True)); { False }



  { 是否包含透明信息 }

  b := IsAlphaPixelFormat(Image.PixelFormat);

  ShowMessage(BoolToStr(b, True)); { False }



  { 是否是 32 位 }

  b := IsCanonicalPixelFormat(Image.PixelFormat);

  ShowMessage(BoolToStr(b, True)); { False }



  { 是否是 64 位 }

  b := IsExtendedPixelFormat(Image.PixelFormat);

  ShowMessage(BoolToStr(b, True)); { False }

end;


 
   

是否是多帧图像(只有 TIFF 和 GIF 才可能是多帧):

---

uses GdiPlus;



procedure TForm1.Button1Click(Sender: TObject);

var

  Tiff,Gif: IGPImage;

  n: Integer;

begin

  Tiff := TGPImage.Create('C:\GdiPlusImg\MultiFrame.tif');

  Gif := TGPImage.Create('C:\GdiPlusImg\Apple.gif');



  if IsEqualGUID(Tiff.RawFormat, ImageFormatTIFF) then

  begin

    n := Tiff.GetFrameCount(FrameDimensionPage);

    ShowMessage(IntToStr(n)); //4

  end;



  if IsEqualGUID(Gif.RawFormat, ImageFormatGIF) then

  begin

    n := Gif.GetFrameCount(FrameDimensionTime);

    ShowMessage(IntToStr(n)); //1

  end;

end;


 
   

调色板:

---

uses GdiPlus;



procedure TForm1.Button1Click(Sender: TObject);

var

  Image: IGPImage;

  Palette: IGPColorPalette;

  i: Integer;

  str: string;

begin

  Image := TGPImage.Create('C:\GdiPlusImg\Stripes.bmp');

  Palette := Image.Palette;

  ShowMessage(IntToStr(Image.Palette.Count)); //5; 若是 0 表示无调色板



  { 也可用下面这句判断是否使用了索引色(或者说调色板) }

  //if not IsIndexedPixelFormat(Image.PixelFormat) then Exit;



  { 以字符串的形式获取调试板中的所有颜色 }

  for i := 0 to Palette.Count - 1 do

  begin

    str := str + Format('$%.8X', [Palette.Entries[i]]) + sLineBreak;

  end;

  ShowMessage(str); { $FF000000/$FFFFFFFF/$FF0000FF/$FF00FF00/$FFFF0000 }

end;