With out the timeout, when it jumps to the next function dataURL ="data:," not dataURL="data:,/png;base64,iVBORw........etc",
so I assume it takes needs time to write the rest of the data string, which makes it asynchronous behavior Roger[Excell] On Jul 21, 3:07 am, Jesse MacFadyen <[email protected]> wrote: > The call canvas.toDataUrl should be synchronous so your timeout would not be > set until after the call had completed. > > Have you observed asynchronous behavior? > > Sent from my iPhone > > On 2010-07-20, at 4:48 PM, Excell <[email protected]> wrote: > > > I am having some success in achieving what my aim was using simple > > code. > > But I have one question > > > I have had to use a setTimeout to wait for the canvas.toDataURL() to > > complete before saveing the data. > > > This is not a great way to move forward as depending on the size of > > the image will change the amount of time i would need to set. > > > Is there anyway to know when canvas.toDataUrl() is complete > > > maybe I am coding this wrong > > > Hope that makes sense > > > <sample code below> > > function drawImage(img) { > > var canvas = document.createElement("canvas"); > > canvas.width = img.width; > > canvas.height = img.height; > > var ctx = canvas.getContext("2d"); > > ctx.drawImage(img,0,0); > > var dataURL = canvas.toDataURL(); > > setTimeout(insert(dataURL),2000);//delay enough for the canvas to be > > converted and save to local database > > > //insert(dataURL); > > //this.cacheImageData(img.src, dataURL); > > } > > > Thanks > > > Roger[Excell] > > > On Jul 16, 7:14 pm, Bill Humphries <[email protected]> wrote: > >> On Jul 16, 2010, at 11:08 AM, Jesse MacFadyen wrote: > > >>> Here's how to get the data from an image. > >>>http://blogs.nitobi.com/jesse/2009/09/24/image-caching-with-the-html5... > > >> Thanks, Jesse. That's much more succinct than my example. Bookmarkiing it. > > >> -- Bill Humphrieshttp://whump.com > > > -- > > You received this message because you are subscribed to the Google Groups > > "iPhoneWebDev" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group > > athttp://groups.google.com/group/iphonewebdev?hl=en. -- You received this message because you are subscribed to the Google Groups "iPhoneWebDev" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/iphonewebdev?hl=en.
