Setup

Assign the command ocrdesktop to a keyboard shortcut in your desktop environment.
e.g., In Gnome or Unity you can do this via the Gnome Control Center in the Keyboard window in the Shortcuts tab.
For languages other than english, set your language code with ocrdesktop -l <languagecode>. Use the tesseract language codes for <languagecode>
You also can use other parameters to expand the function when starting OCRdesktop,
Of course the program can be run via your desktop's run box or dash, but running from a terminal may not be desirable as the terminal window will be in ocrdesktop's screenshot.
Tip Make at least two shortcuts, one without options to capture the active window only, and another with -d to take a screenshot of the whole desktop

Usage

ocrdesktop when run with no commandline options shows the processed output of the active window.
Run ocrdesktop with the -d switch and the whole desktop is processed.
If the OCR quality is not good in the first processing of a screenshot there are transformation options that may improve character recognission accuracy.
To use these options take new screenshots using one or more transformation flags. Available transformations options are:
-i will invert foreground and background color or tone.
<-g uses a gray scale instead of original colors.
-b uses a barier blackwhite method. This method uses the gray scale, and sets a barier wheere all shades darker than the barier are considered black, and everything lighter is seen as white. The default barier is 200, but can be set on the commandline. This method is useful when working with very bright colors or blurry text.
Open menus to see all available options.
They are devided in to three categories, ocrdesktop, interact and macros. There are keyboard shortcuts for all ocrdesktop options. In ocrdesktop you find toggle view, send to clipboard and quit. Interact has controls for simulated mouse clicks etc. The macros menu lets you load, unload, and save macros.

Macros

In most desktop environments, global shortcuts don't work while menus are open, e.g., the file menu in the menu bar at the top of most programs. Ocrdeskop can use preclicks, macros that can be run before the screenshot is taken. This allows you to close all menus and let OCRdesktop click on the menu before it recognizes the window.

To use preclick macros press on preclick in the interact menu, or use the control p shortcut. Then choose a mouse click to perform before OCRdesktop starts the next time. After you click on the button that starts a mouse click, nothing will happen. next time you run OCRdesktop, it will ask what to do. You can press Run, so all stored clicks will execute. After that OCRdesktop takes its screen shot for OCR on the screen as it is after the click action has been performed. Use the Save As option and Preclick and Save As again and the second click will also be stored, e.g. for opening a sub menu.
You can also fire keyboard shortcuts into the preclick macros. To enter the shortcut recording mode, press Ctrl+k or select the Send Key menue entry in the Interact menu. Now every keystroke you type is appended to the currently active preclick macro. Pressing F4 will leve the recording mode. Leving the shortcut recording mode may have a delay of up to 2 seconds.
You can save as many mouse operations as you want.
Choose unload in the macro window to erase the macro, so its lost. If you press Cancel, no mouse clicks are performed, but the main window opens. The
macro will not be deleted and you will be asked next time you start OCRDesktop if you want to run your stored clicks.
Tip: Macros are stored in ~/.activeOCRMacro.ocrm The Save As option lets you store macros in another location if yu choose. It will open a standard file chooser window where you select a name and location for your macro file.