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!
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> --
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>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> --
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>>>>
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>>
>>
>>
>> --
>>
>> Alain Ekambi
>>
>> Co-Founder
>>
>> Ahomé Innovation Technologies
>>
>> http://www.ahome-it.com/ <http://ahome-it.com/>
>>
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>
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--
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Co-Founder
Ahomé Innovation Technologies
http://www.ahome-it.com/ <http://ahome-it.com/>
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