How can I make this code (that is usually in a loop) faster and efficiently?

Question

When I have a place with limited space, where I entry a text that can be few letters or huge amount of text because it's dynamic, I'm using this code to make the text fit the specific space.

#region TextSizing
string textSizing = databaseTable.Description;
using (System.Drawing.Graphics g = System.Drawing.Graphics.FromHwnd(IntPtr.Zero))
{
 size = g.MeasureString(textSizing, new System.Drawing.Font("Arial", 14)).Width;
}
if (size < 1500)
 lblText.Text = textSizing;
else
 lblText.Text = textSizing.Length > 135 ? textSizing.Remove(135) + "..." : textSizing;
#endregion

A friend of mine suggested that I should use cache to store the Font and the Graphics, I didn't understand it very well, but keep thinking about it... How can I make this code (that is usually in a loop) faster and efficiently ?

• Michel Ayres: Not sure how to put a good title for this question, so please feel free to change it so it can be fit more the Q&A format. thanks.
• ANeves: You should use the unicode character ellipsis ..., and not three dots. You might also be interested in gist.github.com/4250125

Answer 1

Cache the instance of Graphics and Font objects so that you don't need to create them each time you measure the length of string. I've created a small test to see which part takes most of the time:

private static void Main()
{
 Stopwatch stopwatch = Stopwatch.StartNew();
 stopwatch.Restart();
 for (int i = 0; i < 1000000; i++)
 {
 using (System.Drawing.Graphics g = System.Drawing.Graphics.FromHwnd(IntPtr.Zero))
 {
 var size = g.MeasureString("asdasdf", new System.Drawing.Font("Arial", 14)).Width;
 }
 }
 Console.WriteLine("Current solution - create a new Graphics per measure: {0} milliseconds", stopwatch.ElapsedMilliseconds);
 stopwatch.Restart();
 using (System.Drawing.Graphics g = System.Drawing.Graphics.FromHwnd(IntPtr.Zero))
 {
 for (int i = 0; i < 1000000; i++)
 {
 var size = g.MeasureString("asdasdf", new System.Drawing.Font("Arial", 14)).Width;
 }
 }
 Console.WriteLine("Measure the string with Graphics cached: {0} milliseconds", stopwatch.ElapsedMilliseconds);
 stopwatch.Restart();
 using (System.Drawing.Graphics g = System.Drawing.Graphics.FromHwnd(IntPtr.Zero))
 using (var font = new System.Drawing.Font("Arial", 14))
 {
 for (int i = 0; i < 1000000; i++)
 {
 var size = g.MeasureString("asdasdf", font).Width;
 }
 }
 Console.WriteLine("Measure the string with Graphics and font cached: {0} milliseconds", stopwatch.ElapsedMilliseconds);
}

Results on my computer are:

Current solution - create a new Graphics per measure: 26864 milliseconds
Measure the string with Graphics cached: 6588 milliseconds
Measure the string with Graphics and font cached: 803 milliseconds

So by caching Graphics you'll reduce the time consumption by 75%, and by caching both Font and Graphics you get a nice 33.5X performance boost :).

• Michel Ayres: Thank you very much for your hard work. This help me more than I expected =)
• Michel Ayres: Now I just need to figure out a way to do this as a method.
• almaz: @MichelAyres see updated answer for better results :)