Asp.net: change the text color in Image dynamically - Free Asp.Net,MVC,AngularJs,Jquery,Javascript,Sql Server,WCF,Entity framework snippets and tutorial

Asp.net: change the text color in Image dynamically

In this article today I am going to explain how to change the text color in Image in Asp.net.

Description:
Asp.net: change the text color in Image dynamically


To change the text color in image I have use the transparent image. In this example I have keep the transparent image in images folder. On button click to change color I have create a new image and save to image folder.




Implementation:
HTML Markup:
  <table>
    <tr>
   <td colspan="2">
        <asp:Image ID="Image1" runat="server" ImageUrl="images/n.png" /></td>
    </tr>
    <tr>
    <td><asp:Button ID="Button1" runat="server" Text="Green" /></td><td><asp:Button ID="btnred"
            runat="server" Text="Red" /></td>
    </tr>
    </table>

Add the Namespace

C#:
using System.IO;
using System.Drawing.Imaging;
using System.Drawing;

VB:
Imports System.IO
Imports System.Drawing.Imaging
Imports System.Drawing

Add the below given function code file 
C#:
private Bitmap ChangeImageColor(System.Drawing.Image source, Color nCol)
    {
        Bitmap bmp = new Bitmap(source);
        for (int y = 0; y < bmp.Height; y++)
        {
            for (int x = 0; x < bmp.Width; x++)
            {
                Color col = bmp.GetPixel(x, y);
                if (col.A != 0)                {
                    int r = (int)(nCol.R);
                    int g = (int)(nCol.G);
                    int bmap= (int)(nCol.B);
                    int light = 0;
                    Color newColor = Color.FromArgb(
                    (r + light > 255 ? r : r + light),
                    (g + light > 255 ? g : g + light),
                    (bmap+ light > 255 ? bmap: bmap+ light));
                    bmp.SetPixel(x, y, newColor);
                }
            }
        }
        return bmp;
    }

VB:
Private Function ChangeImageColor(source As System.Drawing.Image, nCol As Color) As Bitmap
        Dim bmp As New Bitmap(source)
        For y As Integer = 0 To bmp.Height - 1
            For x As Integer = 0 To bmp.Width - 1
                Dim col As Color = bmp.GetPixel(x, y)
                If col.A <> 0 Then
                    'non alpha or any matched color
                    Dim r As Integer = CInt(nCol.R)
                    Dim g As Integer = CInt(nCol.G)
                    Dim b As Integer = CInt(nCol.B)
                    ' To make the image brighter, increase this number
                    Dim light As Integer = 0
                    ' Create the new gray color
                    Dim newColor As Color = Color.FromArgb((If(r + light > 255, r, r + light)), (If(g + light > 255, g, g + light)), (If(b + light > 255, b, b + light)))
                    bmp.SetPixel(x, y, newColor)
                End If
            Next
        Next
        Return bmp
    End Function

Change the color
I have added 2 buttons to change the text color (Red and Green). On their click write the below given code.
C#:
   protected void Button1_Click(object sender, EventArgs e)
    {
        try
        {
        Color NewCol = Color.Green;       
        Bitmap bmap = new Bitmap(Server.MapPath(Image1.ImageUrl));
        bmap = ChangeImageColor((System.Drawing.Image)bmap, NewCol);
        System.IO.MemoryStream mss = new System.IO.MemoryStream();
        bmap.Save(Server.MapPath("~/images/97.png"), ImageFormat.Png);
        Image1.ImageUrl = "~/images/97.png";
        bmap.Dispose();
          }
        catch (Exception ex)
        { }
    }
    protected void btnred_Click(object sender, EventArgs e)
    {
        try
        {
            Color NewCol = Color.Red;
            Bitmap bmap= new Bitmap(Server.MapPath(Image1.ImageUrl));
            bmap = ChangeImageColor((System.Drawing.Image)bmap, NewCol);
            System.IO.MemoryStream mss = new System.IO.MemoryStream();
            bmap.Save(Server.MapPath("~/images/87.png"), ImageFormat.Png);
            Image1.ImageUrl = "~/images/87.png";
            bmap.Dispose();
        }
        catch (Exception ex)
        { }
    }

VB:
  Protected Sub Button1_Click(sender As Object, e As System.EventArgs) Handles Button1.Click
        Try
            Dim NewCol As Color = Color.Green
            Dim bmap As New Bitmap(Server.MapPath(Image1.ImageUrl))
            bmap = ChangeImageColor(DirectCast(bmap, System.Drawing.Image), NewCol)
            Dim mss As New System.IO.MemoryStream()
            bmap.Save(Server.MapPath("~/images/97.png"), ImageFormat.Png)
            Image1.ImageUrl = "~/images/97.png"
            bmap.Dispose()
        Catch ex As Exception

        End Try
    End Sub
    Protected Sub btnred_Click(sender As Object, e As System.EventArgs) Handles btnred.Click
        Try
            Dim NewCol As Color = Color.Red
            Dim bmap As New Bitmap(Server.MapPath(Image1.ImageUrl))
            bmap = ChangeImageColor(DirectCast(bmap, System.Drawing.Image), NewCol)
            Dim mss As New System.IO.MemoryStream()
            bmap.Save(Server.MapPath("~/images/87.png"), ImageFormat.Png)
            Image1.ImageUrl = "~/images/87.png"
            bmap.Dispose()
        Catch ex As Exception

        End Try
    End Sub

Build and run the project. Test it.


    In this article we have learn to how to change the text color in image dynamically in asp.net using C# and VB.netI hope you enjoyed this article. 

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