PILPython图像处理模块.ppt

PythonImageLibraryPIL,10/13/05,PILWhatisit?,PythoniclibraryforLoadingandSavingimages(diverseformats)Scaling,cropping,compositing,transforms,bands(e.g.alphachannel)DrawingtextandbasicshapesAkintotheprogramGIMP(*GIMPalsohasanicepythonAPIcalledGIMP-Python),PIL-Examples,ImageresizingorformatconversionsAddingsave/loadsupportintoyourapplication*FontsupportalsohandyChartgeneration(alsoseePIDDLE)ThumbnailgenerationWatermarkingoraddinglegend,PILAPI-Concepts,ImagefromfileornewlycreatedimportImageim=Image.open(“vacation.jpeg)newIm=Image.new(“RGBA”,(640,480),(255,0,0)Formatfileformatprintim.mode,im.size,im.formatRGB(1024,768)JPEGim.save(“vacation.png”)ORim.save(“vacation.png”,“PNG”),PILAPI-Concepts,ResamplingFiltersNEAREST,BILINEAR,BICUBIC,ANTIALIASsmallIm=im.resize(128,128),Image.ANTIALIAS)SizestupleofwidthandheightBoundingboxestuplesofx1,y1,x2,y20,0isalwaysupperleft,PILAPI-Concepts,Modegrayscale“L”,color“RGBA”“RGB”,etc.1(1-bitpixels,blackandwhite,storedwithonepixelperbyte)L(8-bitpixels,blackandwhite)P(8-bitpixels,mappedtoanyothermodeusingacolourpalette)RGB(3x8-bitpixels,truecolour)RGBA(4x8-bitpixels,truecolourwithtransparencymask)CMYK(4x8-bitpixels,colourseparation)YCbCr(3x8-bitpixels,colourvideoformat)I(32-bitintegerpixels)F(32-bitfloatingpointpixels)Colorspecifiedas32bitvalue,tuple,orstringmyColor=(255,0,0,128)#fullred,with50%alphamyColor=0 x7f0000ff#fullred,with50%alphamyColor=“#00ff00”#webcolormyColor=“rgb(75%,0%,0%)”myColor=“hsl(0,100%,50%)”,PILAPI-Concepts,Bandstheseparatecolorchannelsbands=im.split()rIm=bands0aIm=bands3remadeImage=Image.merge(“RGBA”,(rIm,gIm,bIm,aIm)grayscaleIm=Image.open(“myAlpha.gif”)remadeImage=myImage.putalpha(grayscaleIm)#replacethealphaband,PILSlicing&Dicing,ThumbnailsModifiesin-placePreservesaspectratiomyImage.thumbnail(128,128),Image.ANTIALIAS)Cropbounds=(100,100,400,400)cutoutIm=myImage.crop(bounds)Paste,PILSlicing&Dicing,Blend/compositeRotateTransposeROTATE_90/180/270,FLIP_TOP_BOTTOM,FLIP_LEFT_RIGHTfixedIm=myImage.transpose(ROTATE_90),PIL-Drawing,ImageDrawmodulecreatesdrawingsurfaceforimageimportImage,ImageDrawim=Image.open(“vacation.jpeg)drawSurface=ImageDraw.Draw(im)importImage,ImageDrawim=Image.open(“vacation.jpeg)im.getpixel(4,4)im.putpixel(4,4),(255,0,0),PIL-Drawing,Basicmethodsofdrawingsurfacechordarcpieslice(bounds,strtAng,endAng)ellipse(bounds)line(coordSeq)point(coordSeq)polygon(coordSeq)rectangle(bounds)#firstcoordinclusive,secondcoordexclusvieCommonoptionalargsforthesemethodsfill=fillColoroutline=outlineColor,PILDrawingText,TextdrawSurface=ImageDraw.Draw(im)drawable.text(10,10),“Hello”,fill=(255,0,0),font=None)TrueTypeFontsupportimportImageFontttFont=ImageFont.truetype(“arial.ttf”,16)drawable.text(10,10),“Hello”,fill=(255,0,0),font=ttFont),References,PythonImageLibrary,BMPBUFR(identifyonly)EPS(write-only)FITS(identifyonly)GIFGRIB(identifyonly)HDF5(identifyonly)IMJPEGMPEG(identifyonly)MSPPALM(writeonly)PCXPDF(writeonly)PNGPPMTIFFWMF(identifyonly)XBMXVThumbnails,CUR(readonly)DCX(readonly)FLI,FLC(readonly)FPX(readonly)GBR(readonly)GD(readonly)ICO(read