Introduction
In my previous article, “Web Painting Tool Using HTML 5 CANVAS in ASP.NET", I explained how to create a simple Web Painting tool using HTML5 and jQuery. This article explains how to create a simple web-based photo editing tool using HTML5, jQuery and ASP.NET.
This article shows the details of how to do the following:
- Capture an image from a web camera (I used Webcam JS, you can download the script file from this link).
Webcam JS is a JavaScript library for capturing images from a web camera and saving them as JPEG/PNG or any data URI format.
I used this library to capture images from the web camera and display the captured image in the HTML 5 canvas for editing the photo, adding a smiley, text and sending the final edited image by email. - Add Sticker: Add stickers, for example lSmiley's, flowers, and so on to our captured photo.
- Add Border: Add a border to the captured photo.
- Add Text: Add text to the captured photo.
- Add Filters: Add filters to the captured photo, such as adding contrast, changing it to a Black & White photo, invert the color of the photo or convert to an original captured photo.
- Save and Send to Email: The final edited photo can be saved to the application root folder and you can send the edited photo to an Email address.
- Post Canvas Photo to Facebook: The Final Edited photo can be posted to Facebook.
Prerequisites
- Visual Studio 2013 or Visual Studio 2010
In the source code zip file, you can find both Visual Studio 2010 and Visual Studio 2013 solutions. You can use any solution depending on your Visual Studio version. - Web Camera (to capture your photo to edit and send to email).
Using the Code
The main purpose is to make the program very simple and easy to use. All the functions have been well commented in the project. I have attached my sample program to this article for more details. Here, we will see the procedure to create a photo editing tool using an HTML5 canvas.
HTML5
HTML5 is the new version of HTML. HTML5 has cross-platform support. That means that HTML5 can work on a PC, Tablet and a Smartphone. HTML5 should be started with a DOCTYPE, for example:
<!DOCTYPE html> <html> <body></body> </html>
Step 1: Add References
Add an entire JavaScript library to your project to use the webcam capture. For webcam capture, we need webcam.js, webcam.min.js and webcam.swf. You can download these files from here.
Step 2 - To Add the Webcam
Add this below code to initialize the Web camera in your browser and display the web camera image:
<table >
<tr>
<td align="center">
<div id="my_camera"></div>
<script language="JavaScript">
Webcam.set({
width: 320,
height: 240,
image_format: 'jpeg',
jpeg_quality: 90
});
Webcam.attach('#my_camera');
</script>
</td>
</tr>
<tr>
<td align="center">
<input type=button value="Capture Photo" onClick="takePhoto()">
</td>
</tr>
</table>
To Capture the Image
In Capture button client click event, call the method takePhoto(). In this method, using the webcam.js snap method we receive the Image from the live webcam. I store the resultant image to the global variable and called the init method to add this photo to HTML5 Canvas tag.
function takePhoto() {
Webcam.snap(function (data_uri) {
imageObj_BG.src = data_uri;
init('BG', '');
});
}
Step 3 – Add HTML Canvas Tag
Create a Canvas ELEMENT and declare the global variables and initialize the Canvas in JavaScript. In the code, I have used comments to easily understand the declarations.
HTML Canvas Part
<SECTION style="border-style: solid; border-width: 2px; width: 600px;">
<CANVAS HEIGHT="452" WIDTH="600px" ID="canvas">
Your browser is not supporting HTML5 Canvas.
Upgrade Browser to view this program or check with Chrome or in Firefox.
</CANVAS>
</SECTION>
JavaScript Declaration Part
First, add all the JavaScript references and styles to your ASP.NET page as in the following:
<meta http-equiv="x-ua-compatible" content="IE=9" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<script type="text/javascript" src="Scripts/jquery-1.10.2.min.js"></script>
<script type="text/javascript" src="webcam.js"></script>
<link href="Content/myStyle.css" rel="stylesheet" type="text/css" />
Declare all the variables which need to be used for photo editing. In each declaration, I have added a comment which will explain each use.
<SCRIPT>
var canvas;
var ctx;
var canvasEffect;
var ctxEffect;
var WIDTH = 600;
var HEIGHT = 452;
var Colors = "";
var newPaint = false;
var DrawingTypes = "";
var radius = 30;
var radius_New = 30;
var stickerWidth = 40, stickerHeight = 40;
rect = {},
drag = false;
var rectStartXArray = new Array();
var rectStartYArray = new Array();
var rectWArray = new Array();
var rectHArray = new Array();
var rectColor = new Array();
var DrawType_ARR = new Array();
var radius_ARR = new Array();
var Text_ARR = new Array();
var ImageNames = new Array();
var imageCount = 0;
var imageObj = new Image();
var imageObj_BG = new Image();
var newImagename = '';
var isEffectadded = 'NO';
var EffectType = 'black';
var DrawBorder = "No";
function clear() {
ctx.clearRect(0, 0, WIDTH, HEIGHT);
}
init() Method
init is important since for each button click, this function will be called and pass the parameter for each function type. In this method, I will create an object for the canvas and this canvas object will be used in all other functions. Here, for example, the DrawType will be DrawImage, DrawText, DrawBorder, Place Photo as BG and Filter Effects and the Imagename parameter will be used to pass each sticker image name and so on. In this init method, I will create Mouse events such as Mousedown, Mousemove and MouseUp to add a sticker, move a sticker, resize a sticker and so on.
function init(DrawType, ImageName) {
newPaint = true;
canvas = document.getElementById("canvas");
ctx = canvas.getContext("2d");
canvasEffect = document.getElementById("canvas");
ctxEffect = canvasEffect.getContext("2d");
x = 5;
y = 5;
if (ImageName) {
ImageNames[imageCount] = ImageName;
imageCount = imageCount + 1;
}
DrawingTypes = DrawType;
if (DrawType = 'BG') {
ctx.drawImage(imageObj_BG, 1, 1, canvas.width - 1, canvas.height - 1);
}
if (DrawingTypes == 'Effects') {
isEffectadded = 'YES';
EffectType = ImageName;
Effects();
}
radius = 30;
radius_New = radius;
canvas.addEventListener('mousedown', mouseDown, false);
canvas.addEventListener('mouseup', mouseUp, false);
canvas.addEventListener('mousemove', mouseMove, false);
return setInterval(draw, 10);
}
Add Captured Photo to Canvas
For example, to add the captured photo to the canvas, we call the takePhoto method.
<input type=button value="Capture Photo" onClick="takePhoto()">
We have already seen that in takePhoto, we store the captured photo to a global image variable.
function takePhoto() {
Webcam.snap(function (data_uri) {
imageObj_BG.src = data_uri;
init('BG', '');
});
}
In this method, I called init('BG', '') and in the init method, I will check the DrawType = 'BG'. If it's true, then I will draw the captured image to the canvas as in the following:
if (DrawType = 'BG') {
ctx.drawImage(imageObj_BG, 1, 1, canvas.width - 1, canvas.height - 1);
}
Add border/text/Sticker to Captured Photo
In the Border Image click event, I passed the DrawType as "Border" and in the mouse move event, I will call the draw() method. This method depends on the DrawingTypes selected. I will add the features to the canvas tag, for example if Border is selected, then I will draw the border for the canvas tag. If Images is selected, then I will add the selected sticker image to the canvas tag.
<img src="images/rect.png" onClick="init('Border','')" />
<img src="images/Font.png" onClick="init('DrawText','')" />
<img src="images/smily8.png" width="36" height="36"
onClick="init('Images','images/smily8.png')"/>
<img src="images/smily9.png" width="36" height="36"
onClick="init('Images','images/smily9.png')"/>
<img src="images/smily10.png" width="36" height="36"
onClick="init('Images','images/smily10.png')"/>
function draw() {
ctx.beginPath();
Colors = document.getElementById("SelectColor").value;
ctx.fillStyle = "#" + Colors;
switch (DrawingTypes) {
case "Border":
ctx.strokeStyle = "#" + Colors;
ctx.lineWidth = 10;
ctx.strokeRect(0, 0, canvas.width, canvas.height)
DrawBorder = "YES";
break;
case "Images":
imageObj.src = ImageNames[imageCount - 1];
ctx.drawImage(imageObj, rect.startX, rect.startY, rect.w, rect.h);
break;
case "DrawText":
ctx.font = '40pt Calibri';
ctx.fillText($('#txtInput').val(), drawx, drawy);
break;
}
ctx.fill();
}
Add Filter Effects to Captured Photo
To add the filter effects to the captured photo, I created an Effects function. This method depends on the user clicked effect. I will change the photo to either Black & White, Contrast, Invert or original Image.
<input type=button value="Black&White" onClick="init('Effects', 'black')"/>
<input type=button value="Contrast" onClick="init('Effects', 'contrast')"/>
<input type=button value="Invert Color" onClick="init('Effects', 'invertColors')"/>
<input type=button value="OriginalImage" onClick="init('Effects', 'OriginalImage')"/>
function Effects() {
if (isEffectadded == 'YES') {
var imgd = ctxEffect.getImageData(0, 0, canvas.width, canvas.height);
var pix = imgd.data;
switch (EffectType) {
case "black":
for (var i = 0, n = pix.length; i < n; i += 4) {
var grayscale = pix[i] * .3 + pix[i + 1] * .59 + pix[i + 2] * .11;
pix[i] = grayscale;
pix[i + 1] = grayscale;
pix[i + 2] = grayscale;
}
ctxEffect.putImageData(imgd, 0, 0);
break;
case "contrast":
var contrast = 40;
var factor = (259 * (contrast + 255)) / (255 * (259 - contrast));
for (var i = 0; i < pix.length; i += 4) {
pix[i] = factor * (pix[i] - 128) + 128;
pix[i + 1] = factor * (pix[i + 1] - 128) + 128;
pix[i + 2] = factor * (pix[i + 2] - 128) + 128;
}
ctxEffect.putImageData(imgd, 0, 0);
break;
case "invertColors":
for (var i = 0; i < pix.length; i += 4) {
pix[i] = 255 - pix[i];
pix[i + 1] = 255 - pix[i + 1];
pix[i + 2] = 255 - pix[i + 2];
}
ctxEffect.putImageData(imgd, 0, 0);
break;
case "OriginalImage":
for (var i = 0; i < pix.length; i += 4) {
pix[i] = pix[i];
pix[i + 1] = pix[i + 1];
pix[i + 2] = pix[i + 2];
}
ctxEffect.putImageData(imgd, 0, 0);
break;
}
}
}
Here, we can see each filter photo output. The first we have is a Black & White photo. Change the captured photo to Black & White.
Next, we have Invert Photo. Invert the captured photo as in the following:
Next, we will add Contrast to captured photo as invert like in the following:
Finally, we have the original photo that was captured from the web camera initially.
Save and Send Email
In the send email button client click, I will store the Canvas image to the hidden field.
<asp:Button ID="btnImage" runat="server" Text="Send Email"
OnClientClick = "sendEmail();return true;" onclick="btnImage_Click" />
function sendEmail() {
var m = confirm("Are you sure to Save ");
if (m) {
var image_NEW = document.getElementById("canvas").toDataURL("image/png");
image_NEW = image_NEW.replace('data:image/png;base64,', '');
$("#<%=hidImage.ClientID%>").val(image_NEW);
alert('Image saved to your root Folder and email send !');
}
}
In the code behind button click event, I will get the hidden field value and store the final result image to the application root folder. This image will be used to send an email.
protected void btnImage_Click(object sender, EventArgs e)
{
string imageData = this.hidImage.Value;
Random rnd = new Random();
string imagePath = HttpContext.Current.Server.MapPath
("Shanuimg" + rnd.Next(12, 2000).ToString() + ".jpg");
using (FileStream fs = new FileStream(imagePath, FileMode.Create))
{
using (BinaryWriter bw = new BinaryWriter(fs))
{
byte[] data = Convert.FromBase64String(imageData);
bw.Write(data);
bw.Close();
sendMail(imagePath);
}
}
}
In the button click event after the image is saved to the root folder, I will send the path to the sendMail method.
In this method using the user entered From and To email address, I will send the photo with the subject and message to the email.
private void sendMail(string FilePath)
{
MailMessage message = new MailMessage();
SmtpClient smtpClient = new SmtpClient();
try
{
MailAddress fromAddress = new MailAddress(txtFromEmail.Text.Trim());
message.From = fromAddress;
message.To.Add(txtToEmail.Text.Trim());
message.Attachments.Add(new Attachment(FilePath));
message.Subject = txtSub.Text.Trim();
message.IsBodyHtml = true;
message.Body = txtMessage.Text.Trim();
smtpClient.Host = "smtp.gmail.com";
smtpClient.Port = 587;
smtpClient.EnableSsl = true;
smtpClient.UseDefaultCredentials = true;
smtpClient.Credentials = new System.Net.NetworkCredential
(userGmailEmailID, userGmailPasswod);
smtpClient.Send(message);
}
catch (Exception ex)
{
}
}
Note: Here, I used the host as smtp.gmail.com and in System.Net.NetworkCredential(userGmailEmailID, userGmailPasswod); you need to provide your Gmail Email address and Gmail password to send the email.
I have declared the variable as global as in the following so that the user can add their own Gmail Email address and Gmail password.
String userGmailEmailID = "YourGamilEmailAddress";
string userGmailPasswod = "YourGmailPassword";
Post Photo to Facebook
To post our photo to Facebook, we need to have a Facebook APPID. To create our APPID, go to https://developers.facebook.com/ and login using your Facebook id.
After Login to create New App ID, enter your display name and click Create App ID.
Now you can see your App ID has been created. You can use this App ID to post your image to Facebook.
Click on Settings and add your website URL in case, if you’re developing as localhost in site URL, you can give the localhost URL as below:
Click Settings - > Advanced and set the Embedded browser OAutho Login to “YES”.
Send to FB
Using Facebook API, we can pass the Canvas converted base64 Image to Facebook using our App ID. Here is the reference link which explains how to convert and embed HTML5 Canvas 5 Image to base64.
<INPUT TYPE ="Button" id="btnFB" VALUE=" Send to FB " onClick="sendtoFB()">
function sendtoFB() {
var m = confirm("Are you sure Post in FaceBook ");
if (m) {
$.getScript('//connect.facebook.net/en_US/all.js', function () {
// Load the APP / SDK
FB.init({
appId: 'yourFaceBookAppID', // App ID from the App Dashboard
cookie: true, // set sessions cookies to allow
// your server to access the session?
xfbml: true, // parse XFBML tags on this page?
frictionlessRequests: true,
oauth: true
});
FB.login(function (response) {
if (response.authResponse) {
window.authToken = response.authResponse.accessToken;
PostImageToFacebook(window.authToken)
} else {
}
}, {
scope: 'publish_actions'
});
});
}
}
When user clicks on Send to FB button, they can login to their Facebook for posting the canvas Photo.
Once the photo has been posted, we can see our new photo in our Facebook page.
Note: If your posted Photo on Facebook is not visible to other users, then you have to set your app to live. To make your app live, go to your App Facebook page and select Settings and make "Do you want to make this app and all its live features available to the general public?"
Tested Browsers
- Chrome
- Firefox
- Internet Explorer 10
History
- 10th June, 2015: Initial version
