Generating Images Dynamically in ASP.NET

else if(sColor == "Blue")

{

ocolor = Color.Blue;

}

else if(sColor == "Green")

{

ocolor = Color.Green;

}

Next, we create two brushes, which will help us to draw our image. The first one, oBrush, will be used to draw the background of the image:

SolidBrush oBrush = new SolidBrush(ocolor);

The second brush will be used to draw the text entered by the user; we hardcode the brush color as white.

SolidBrush oBrushWrite = new SolidBrush(Color.White);

We're going to use the first brush to fill the image rectangle, because the default color of new bitmaps is black. We call the FillRectangle method of oGraphic to paint the background in the color selected by the user (oColor):

oGrp1.FillRectangle(oBrush,0,0,500,75);

So far, we've changed the background color of our image, but we haven't written any text. We'll use the DrawString method of the oGraphic object to do that. The DrawString method has several overloads. This is the one we're going to use:

DrawString(String,Font,Brush,Fpoint);

The first parameter is just the string that we want to write; the second parameter defines the font to be used; the third parameter defines a brush (this will be the second brush we created above); the last parameter defines a drawing starting point relative to the top-left corner of our image. Before we call the DrawString method, however, we need to create an instance of the Font class, and FPoint structure that defines the point at which drawing should start.

The user chose a font for the text, so we pass sFont as the first parameter, and hardcode the second parameter, which defines the font size:

Font oFont = new Font(sFont,13);
PointF oPoint = new PointF(5F,5F);

so now we created instances of Font and PointF and now DrawString parameters are ready:

oGrp1.DrawString(sText,oFont,oBrushWrite,oPoint);

Now the last thing is we have to send the image to browser for that.

Response.ContentType = "image/jpeg" ;
oBmp1.Save (Response.OutputStream, ImageFormat.Jpeg);

That's all we generated a Text image dynamically at run time.

The below image shows the sample output:



Figure 1.

Summary:

This article explains how to create simple images dynamically at runtime.