Is there a way to see what format the file has? If it isn't an image i'll have to warn the user.
2016-01-25 14:58 GMT-02:00 Julio Heitor Nobrega <[email protected]>: > Hi Alain, > > nice code! I am going to do this but in a java version code. I just didn't > know i could get the image path from a 'value' of the > > document.getElementById("fileUpload") > > I could even show a image preview to the user before send it to the server! > > Or maybe convert the base64 String to byte array, scale it and then send > to the server :) > > Thanks! > > 2016-01-25 14:22 GMT-02:00 Alain Ekambi <[email protected]>: > >> I think what you should to is get the base64 representation of the image >> from the canvas. Something like >> >> var p;var canvas = document.createElement("canvas"); >> var img1=document.createElement("img"); >> function getBase64Image(){ >> p=document.getElementById("fileUpload").value; >> img1.setAttribute('src', p); >> canvas.width = img1.width; >> canvas.height = img1.height; >> var ctx = canvas.getContext("2d"); >> ctx.drawImage(img1, 0, 0); >> var dataURL = canvas.toDataURL("image/png");alert("from getbase64 >> function"+dataURL ); >> return dataURL;} >> >> Then send the base64 to the server and corvert it to byterarry or >> whatever format you need there to save it to disc, >> >> >> >> On 25 January 2016 at 17:11, Julio Heitor Nobrega < >> [email protected]> wrote: >> >>> Hi Alain, >>> >>> i am doing exactly that. I am sending the byte array to the server, >>> saving it as a file in a directory and storing the path in a DB column. >>> >>> My problem is to get the byte array from the file (is it possible to get >>> the byte array using FileUpoad?) and work on it before send to the server. >>> >>> 2016-01-25 13:39 GMT-02:00 Alain Ekambi <[email protected]>: >>> >>>> Would it be a better designer to save the image on disc and just save >>>> the link to the image to the DB ? >>>> >>>> On 25 January 2016 at 15:59, Julio Heitor Nobrega < >>>> [email protected]> wrote: >>>> >>>>> As a matter of fact, i am beginning to think that its more wise to >>>>> send the whole image to the server, scale it using Scalr and store it into >>>>> the DB. >>>>> >>>>> I want to have the control of the image size, test levels of quality. >>>>> The Scalr has a mode called 'Automatic' that fits your image to the >>>>> dimensions you pass to it. >>>>> >>>>> None of it i will have with GWT Canvas. >>>>> >>>>> The only drawback i would get using Scalr is that i will consume more >>>>> bandwidth DigitalOcean gives me monthly because i will have to send the >>>>> whole image to the server. >>>>> >>>>> 2016-01-25 12:52 GMT-02:00 Julio Heitor Nobrega < >>>>> [email protected]>: >>>>> >>>>>> Thanks for your answer Greg! >>>>>> >>>>>> Actually, i really need a byte array because i will store it in a >>>>>> BLOB database column. >>>>>> >>>>>> Regards! >>>>>> >>>>>> 2016-01-25 12:43 GMT-02:00 Greg <[email protected]>: >>>>>> >>>>>>> Just use context.getCanvas().toDataUrl(); which will return data uri >>>>>>> with the contents of the canvas. You can use it directly in <img src=""> >>>>>>> element or send it to server. >>>>>>> >>>>>>> On Monday, January 25, 2016 at 3:19:03 PM UTC+1, Julio Heitor >>>>>>> Nobrega wrote: >>>>>>>> >>>>>>>> I have just found an example ( >>>>>>>> http://c.gwt-examples.com/home/ui/canvas). >>>>>>>> >>>>>>>> The only problem is to convert ImageData to an byte array :) >>>>>>>> >>>>>>>> Regards! >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> 2016-01-25 12:08 GMT-02:00 Julio Heitor Nobrega < >>>>>>>> [email protected]>: >>>>>>>> >>>>>>>>> Does anyone have some examples regarding the Canvas class? >>>>>>>>> >>>>>>>>> I've seen the java doc API but the only methods i think that could >>>>>>>>> be useful was: >>>>>>>>> >>>>>>>>> Context2d >>>>>>>>> <http://www.gwtproject.org/javadoc/latest/com/google/gwt/canvas/dom/client/Context2d.html> >>>>>>>>> *getContext2d >>>>>>>>> <http://www.gwtproject.org/javadoc/latest/com/google/gwt/canvas/client/Canvas.html#getContext2d%28%29>* >>>>>>>>> () >>>>>>>>> Returns a 2D rendering context. >>>>>>>>> void *setCoordinateSpaceHeight >>>>>>>>> <http://www.gwtproject.org/javadoc/latest/com/google/gwt/canvas/client/Canvas.html#setCoordinateSpaceHeight%28int%29>* >>>>>>>>> (int height) >>>>>>>>> Sets the height of the internal canvas coordinate >>>>>>>>> space. >>>>>>>>> void *setCoordinateSpaceWidth >>>>>>>>> <http://www.gwtproject.org/javadoc/latest/com/google/gwt/canvas/client/Canvas.html#setCoordinateSpaceWidth%28int%29>* >>>>>>>>> (int width) >>>>>>>>> Sets the width of the internal canvas coordinate space. >>>>>>>>> >>>>>>>>> 2016-01-14 16:36 GMT-02:00 Kirill Prazdnikov <[email protected]>: >>>>>>>>> >>>>>>>>>> Canvas is an DOM Element. >>>>>>>>>> It can render Image Elements to itself in any resolution. >>>>>>>>>> However it may produce not nice results. >>>>>>>>>> >>>>>>>>>> It depends on what you need. >>>>>>>>>> >>>>>>>>>> On Thursday, January 14, 2016 at 9:17:36 PM UTC+3, Julio Heitor >>>>>>>>>> Nobrega wrote: >>>>>>>>>>> >>>>>>>>>>> Hi guys, >>>>>>>>>>> >>>>>>>>>>> thanks everyone for the answers! >>>>>>>>>>> >>>>>>>>>>> Greg, is Canvas a GWT framework or its a class that belong to >>>>>>>>>>> GWT itself? >>>>>>>>>>> >>>>>>>>>>> Do you have any example of use? >>>>>>>>>>> >>>>>>>>>>> Regards >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Em quinta-feira, 14 de janeiro de 2016 11:25:29 UTC-2, Julio >>>>>>>>>>> Heitor Nobrega escreveu: >>>>>>>>>>>> >>>>>>>>>>>> Hi guys, >>>>>>>>>>>> >>>>>>>>>>>> i am trying to upload images with 2mb size but i don't want to >>>>>>>>>>>> send the whole original image to the server. >>>>>>>>>>>> >>>>>>>>>>>> What i would like to do is reduce the image dimensions from, >>>>>>>>>>>> for example, *1000x1000* to *50x50* and reduce the file size >>>>>>>>>>>> from *2mb* to *~25kb* as well and at the end send the *~25kb* >>>>>>>>>>>> image to the server. >>>>>>>>>>>> >>>>>>>>>>>> I know there is the Scalr framework that does that in java, but >>>>>>>>>>>> its no compatible with GWT clients. >>>>>>>>>>>> >>>>>>>>>>>> Is there any client side GWT library that does the same thing >>>>>>>>>>>> as Scalr? >>>>>>>>>>>> >>>>>>>>>>>> Best Regards! >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> -- >>>>>>>>>> You received this message because you are subscribed to a topic >>>>>>>>>> in the Google Groups "GWT Users" group. >>>>>>>>>> To unsubscribe from this topic, visit >>>>>>>>>> https://groups.google.com/d/topic/google-web-toolkit/8OfazCLtcLA/unsubscribe >>>>>>>>>> . >>>>>>>>>> To unsubscribe from this group and all its topics, send an email >>>>>>>>>> to [email protected]. >>>>>>>>>> To post to this group, send email to >>>>>>>>>> [email protected]. >>>>>>>>>> Visit this group at >>>>>>>>>> https://groups.google.com/group/google-web-toolkit. >>>>>>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> -- >>>>>>> You received this message because you are subscribed to a topic in >>>>>>> the Google Groups "GWT Users" group. >>>>>>> To unsubscribe from this topic, visit >>>>>>> https://groups.google.com/d/topic/google-web-toolkit/8OfazCLtcLA/unsubscribe >>>>>>> . >>>>>>> To unsubscribe from this group and all its topics, send an email to >>>>>>> [email protected]. >>>>>>> To post to this group, send email to >>>>>>> [email protected]. >>>>>>> Visit this group at >>>>>>> https://groups.google.com/group/google-web-toolkit. >>>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>>> >>>>>> >>>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "GWT Users" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> To post to this group, send email to >>>>> [email protected]. >>>>> Visit this group at https://groups.google.com/group/google-web-toolkit >>>>> . >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> >>>> >>>> >>>> -- >>>> >>>> Alain Ekambi >>>> >>>> Co-Founder >>>> >>>> Ahomé Innovation Technologies >>>> >>>> http://www.ahome-it.com/ <http://ahome-it.com/> >>>> >>>> -- >>>> You received this message because you are subscribed to a topic in the >>>> Google Groups "GWT Users" group. >>>> To unsubscribe from this topic, visit >>>> https://groups.google.com/d/topic/google-web-toolkit/8OfazCLtcLA/unsubscribe >>>> . >>>> To unsubscribe from this group and all its topics, send an email to >>>> [email protected]. >>>> To post to this group, send email to >>>> [email protected]. >>>> Visit this group at https://groups.google.com/group/google-web-toolkit. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "GWT Users" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To post to this group, send email to [email protected] >>> . >>> Visit this group at https://groups.google.com/group/google-web-toolkit. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> >> -- >> >> Alain Ekambi >> >> Co-Founder >> >> Ahomé Innovation Technologies >> >> http://www.ahome-it.com/ <http://ahome-it.com/> >> >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "GWT Users" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/google-web-toolkit/8OfazCLtcLA/unsubscribe >> . >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at https://groups.google.com/group/google-web-toolkit. >> For more options, visit https://groups.google.com/d/optout. >> > > -- You received this message because you are subscribed to the Google Groups "GWT Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/google-web-toolkit. For more options, visit https://groups.google.com/d/optout.
