PickRGB is a Windows utility to pick up RGB values. It lets you sample colors anywhere on the screen in many color formats.
When you move the cursor around, PickRGB shows the current color under the cursor in several ways:
a COLORREF value
RGB values in hexadecimal [00..FF], decimal [0..255] and floating point [0..1]
a big colored box
a highlighted pixel in a zoomed window
If you press the CTRL key, the current color value is written to the text window below in one of the six formats. This lets you quickly sample a number of color values to be used in your application or wherever. The six formats are saved in the Registry for next time. The formats are standard sprintf format and to the right you can see the arguments to sprintf.
The current (x,y) position of the cursor is continuously displayed.
You can measure size like this: each time you press the CTRL key, the Size: display is reset, and when you move the cursor you can see the size of the box from the position of when the CTRL key was pressed to the current position.