Very Simple Paint

• Download demo project - 61.62 KB

Introduction

I was working on a project and I needed to make some changes to images such as delete and remove information and mark some features using a different type, width and colors to the pencil.

Using the Code

The core of this small code is the usage of the Graphics object. Usually, you can use it to paint something to the picture to provide some information to the client but really you don't paint within a Bitmap structure. In this case, you obtain your goal using the Graphics of visual component like:

Graphics graphics = pictureBox.CreateGraphics();

But this way requires that you do all your paint operations on the paint event of pictureBox because all modifications belong to the visual control and not to the bitmap structure. Besides one application like this should generate several paint events and you must redraw unnecessary things in each paint operation. Due to the reasons previously commented, I did my paint operations using the graphics of bitmap directly like:

Graphics graphics = Graphics.FromImage(bitmap);

You must be careful because you are applying transformations to the original bitmap. First make a copy if you want to save the original image. To obtain the changed image, you must only read the variable bitmap used to create the graphics. In the application, you can see the usage of the Cursor object to visually establish the difference of pencils.

/// <summary>
/// Set the image to pointer
/// </summary>
private void SetMouseCursor()
{
    string name = picBoxClicked.Name;
    switch (name)
    {
        case "picBoxCircleBig":
            Cursor = new Cursor("CursorCircleBig.cur");
            break;
        case "picBoxCircleMedium":
            Cursor = new Cursor("CursorCircleMedium.cur");
            break;
        case "picBoxCircleSmall":
            Cursor = new Cursor("CursorCircleSmall.cur");
            break;
        case "picBoxRecBig":
            Cursor = new Cursor("CursorRectBig.cur");
            break;
        case "picBoxRecMedium":
            Cursor = new Cursor("CursorRectMedium.cur");
            break;
        case "picBoxRecSmall":
            Cursor = new Cursor("CursorRectSmall.cur");
            break;
    }
} 

The files *.cur were created using images edited by myself. All the implementation is very simple but I think that there are some small tips that may be useful for someone. I hope you enjoy this!

History

• 7^th November, 2006: Initial post