After pressing 'Loading a local image', type 'b' to mark the beginning a line at the mouse location, 'e' to mark the line's end.
A line will then be drawn on the image and a graph of the RGB values of the line will appear below the image.
If you position the mouse somewhere on the line and then press 'm', it will mark the line to reflect the percentage position on the line.
Click 'Open Pixel Inspector' to launch the readout in a separate window that shows the RGB & L values of the current mouse position.
The 'Display # of bits' may be used to force the RGB values of the inspector and graph to be either 8 bits (max 255) or 16 bits (max 65,536).
After a line is drawn, the following fields may be set:
The 'Hide line' checkbox can be used to hide the line that is drawn over the image.
The 'Brightness only' checkbox will show only the luminance, not the 3 individual RGB channels. For better visualization, it will also fill the area below the graph with the pixel value at the point being graphed.
The 'Show B&W bars' checkbox (only shown when 'Brightness only' checcked), fills the graph with grayscale bars instead of the original colors.
The 'Scale to min/max' checkbox will scale the display of the intensity values to include most of the vertical space.
The 'Set width...' input fields may be used to adjust the space used by the RGB graph.
The parameters that you currently have selected may be copied to the clipboard by pressing 'c' or by copying the text on the last line of the screen.
Press 'a' to append a snapshot of the current graph and table to the bottom of the screen. This can be repeated to compare several snapshots; each one has a 'Remove' button.