Button image too far from top of button; too close to bottom of button

Question

I'm working on a Windows Form in VB.NET 2005 and I would like to have some buttons with images (I'm talking about the plain, vanilla System.Windows.Forms.Button). I have everything set up the way I want it but the images are displaying too low on the button, such that the bottom of the icon is almost right on the bottom of the button and there is a lot of space above the image.

Here is a screenshot:
Button Screenshot http://www.freeimagehosting.net/uploads/b28a5c63b8.jpg

See how the corner of the icon is brushing up against the bottom of the button?

My button is 23 pixels high and the image is a 16 x 16 icon (converted to a bitmap so that it can be assigned to the button's Image property).

I've tried setting the button's Margin.All property to 0, and verified that the Padding.All property is 0. I've also tried changing the button's ImageAlign to TopLeft, MiddleLeft, and BottomLeft, but none of those settings seem to have any affect.

Does anyone know how I can position the image to be of equal distance from the top and bottom edges of the button? I can resize the button or the image if necessary but they are at my preferred size and I would like to keep them that way if possible.

Answer 1

I just encountered a similar problem, which I was able to solve by thinking really hard. (Ain't those situations great?)

The explanation

First it's important to understand that ImageAlign does NOT mean where on the button do you want the image. It means what point (pixel) on the image should be used for positioning. So if you pick "TopLeft", then the top-left-most pixel of the image will be vertically CENTERED on the button.

The problem comes in when you have a button with a centered image, whose ImageAlign is set vertically to "center", and whose dimensions are of an even number of pixels. Your image is 16x16 pixels- 16 is an even number. The middle pixel would theoretically be somewhere between pixel 8 and pixel 9. Since there is no pixel 8.5, VB rounds down to 8, thereby using pixel 8 as your positioning pixel. This the root cause of your unwanted upper margin.

Your button has an odd pixel height (23px) which means it has a true center pixel- pixel 12. VB tries to position the image's center pixel (8) on top of the button's center pixel (12). This puts 8 of the image's pixels BELOW center, and 7 pixels ABOVE center. To even things out, a 1-pixel margin appears above the image.

The solution

Pad the image with 1 extra row of pixels on the bottom. The image now has a height that's odd (17 px), giving the image a true center pixel which can line up perfectly with the button's center pixel.

That's how I solved the problem for myself. However, a simpler possible solution just occurred to me. You could probably achieve the same result by assigning the image a bottom margin of 1px. I have not tested this solution but it seems theoretically equivalent to the first solution.

Additional note: Two objects of EVEN dimensions should theoretically be able to center-align perfectly. But strangely enough, the alignment problem occurs even if the button AND the image BOTH have even dimensions. (Apparently the compiler is not consistent in the way it determines the center pixel of one control vs another.) Nonetheless, in this case, the same solution applies.

Answer 2

Typically, we'll set the following properties (for an image on the right, for example):

ImageAlign: MiddleRight
TextAlign: MiddleLeft

You'll want to align both the text and image in a similar fashion. Outside of that, make sure that you are setting the Image property, not the BackgroundImage property and make sure you are doing the icon to plain bitmap conversion properly. Have you tried a plain bitmap file?