Yes. That's what I like to do. Could you give an example of retreiving canvas raw data by GWT instead of JSNI?
Kevin On Wed, Mar 4, 2009 at 4:18 AM, Matt Bishop <m...@re-entry.ca> wrote: > > This is pretty cool. You should try converting the data in GWT instead > of JSNI. It could go straight to bytes, or at least it could take > advantage of GWT's StringBuilder speed. > > > On Mar 1, 4:57 pm, Kevin Tarn <kevn.t...@gmail.com> wrote: > > Forgot to tell: getImageData method convert raw data to a Windows DIB > > format. > > > > Kevin > > > > On Mon, Mar 2, 2009 at 8:52 AM, Kevin Tarn <kevn.t...@gmail.com> wrote: > > > I got idea from canvas2image.js( > http://www.nihilogic.dk/labs/canvas2image/). > > > So I wrote a JSNI methods as below: > > > > > public native String getImageData(int left, int top, int width, int > > > height) /*-{ > > > > > var oData = th...@com.messenger.client.framework.canvas > ::context.getImageData(left, > > > top, width, height); > > > > > var aImgData = oData.data; > > > > > var strPixelData = ""; > > > var y = height; > > > var iPadding = (4 - ((width * 3) % 4)) % 4; > > > > > do { > > > var iOffsetY = width*(y-1)*4; > > > var strPixelRow = ""; > > > for (var x=0;x<width;x++) { > > > var iOffsetX = 4*x; > > > > > if (aImgData[iOffsetY+iOffsetX+2] == 0 && > > > aImgData[iOffsetY+iOffsetX+1] == 0 && > > > aImgData[iOffsetY+iOffsetX] == 0) { > > > > > strPixelRow += String.fromCharCode(255); > > > strPixelRow += String.fromCharCode(255); > > > strPixelRow += String.fromCharCode(255); > > > } else { > > > strPixelRow += > > > String.fromCharCode(aImgData[iOffsetY+iOffsetX+2]); > > > strPixelRow += > > > String.fromCharCode(aImgData[iOffsetY+iOffsetX+1]); > > > strPixelRow += > > > String.fromCharCode(aImgData[iOffsetY+iOffsetX]); > > > } > > > } > > > for (var c=0;c<iPadding;c++) { > > > strPixelRow += String.fromCharCode(0); > > > } > > > strPixelData += strPixelRow; > > > } while (--y); > > > > > return strPixelData; > > > }-*/; > > > > > As above method, I got a raw data in String object. So I need another > > > method to convert it to byte array. Here it is: > > > > > public byte[] getBitmap() { > > > String str = getImageData(0, 0, width, height); > > > byte[] ar = new byte[str.length()]; > > > for (int i=0; i<ar.length; i++) > > > ar[i] = (byte)((int)str.charAt(i) & 0xff); > > > return ar; > > > } > > > > > Hope this is helpful. > > > > > Kevin > > > > > On Sat, Feb 28, 2009 at 10:41 PM, FabrÃcio Cabral < > fabrici...@gmail.com>wrote: > > > > >> Could you say how you solved this problem? For historic purpose... > > > > >> Thanks in advance! > > > > >> > I have solved problem. > > > > >> > Kevin > > >> -- > > >> --fx > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to Google-Web-Toolkit@googlegroups.com To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/Google-Web-Toolkit?hl=en -~----------~----~----~----~------~----~------~--~---
