Extras: added screenshots to README.md and instructions for using UI inspectors

flatlaf-extras/README.md

@@ -3,19 +3,20 @@ FlatLaf Extras
 
 This sub-project provides some additional components and classes:
 
-- [FlatAnimatedLafChange](src/main/java/com/formdev/flatlaf/extras/FlatAnimatedLafChange.java):
-  Animated Laf changing.
-- [FlatInspector](src/main/java/com/formdev/flatlaf/extras/FlatInspector.java):
-  A simple UI inspector that shows information about UI component at mouse
-  location in a tooltip.
-- [FlatSVGIcon](src/main/java/com/formdev/flatlaf/extras/FlatSVGIcon.java): An
-  icon that displays SVG using
-  [svgSalamander](https://github.com/JFormDesigner/svgSalamander).
-- [FlatUIDefaultsInspector](src/main/java/com/formdev/flatlaf/extras/FlatUIDefaultsInspector.java):
-  A simple UI defaults inspector that shows a window with all UI defaults used
-  in current theme (look and feel).
-- [TriStateCheckBox](src/main/java/com/formdev/flatlaf/extras/TriStateCheckBox.java):
-  A tri-state check box.
+- [FlatSVGIcon](https://www.javadoc.io/doc/com.formdev/flatlaf-extras/latest/com/formdev/flatlaf/extras/FlatSVGIcon.html):
+  An icon that displays SVG using
+  [svgSalamander](https://github.com/JFormDesigner/svgSalamander).\
+  ![FlatSVGIcon.png](../images/extras-FlatSVGIcon.png)
+- [TriStateCheckBox](https://www.javadoc.io/doc/com.formdev/flatlaf-extras/latest/com/formdev/flatlaf/extras/TriStateCheckBox.html):
+  A tri-state check box.\
+  ![TriStateCheckBox.png](../images/extras-TriStateCheckBox.png)
+- [FlatAnimatedLafChange](https://www.javadoc.io/doc/com.formdev/flatlaf-extras/latest/com/formdev/flatlaf/extras/FlatAnimatedLafChange.html):
+  Animated Laf (theme) changing.
+- [FlatInspector](#ui-inspector): A simple UI inspector that shows information
+  about UI component at mouse location in a tooltip.
+- [FlatUIDefaultsInspector](#ui-defaults-inspector): A simple UI defaults
+  inspector that shows a window with all UI defaults used in current theme (look
+  and feel).
 
 
 Download
@@ -39,3 +40,45 @@ you can download here:
 
 [![Download](https://api.bintray.com/packages/jformdesigner/flatlaf/flatlaf/images/download.svg)](https://bintray.com/jformdesigner/flatlaf/flatlaf/_latestVersion)
 [![Download](https://api.bintray.com/packages/jformdesigner/svgSalamander/svgSalamander/images/download.svg)](https://bintray.com/jformdesigner/svgSalamander/svgSalamander/_latestVersion)
+
+
+Tools
+-----
+
+### UI Inspector
+
+A simple UI inspector that shows information about UI component at mouse
+location in a tooltip, which may be useful while developing an application.
+Should be not installed in released applications.
+
+Once installed with following code (e.g. in method `main`), it can be activated
+for the active window with the given keystroke:
+
+~~~java
+FlatInspector.install( "ctrl shift alt X" );
+~~~
+
+![UI inspector](../images/extras-FlatInspector.png)
+
+When the UI inspector is active some additional keys are available:
+
+- press <kbd>Esc</kbd> key to disable UI inspector
+- press <kbd>Ctrl</kbd> key to increase inspection level, which shows
+  information about parent of UI component at mouse location
+- press <kbd>Shift</kbd> key to decrease inspection level
+
+
+### UI Defaults Inspector
+
+A simple UI defaults inspector that shows a window with all UI defaults used in
+current theme (look and feel), which may be useful while developing an
+application. Should be not installed in released applications.
+
+Once installed with following code (e.g. in method `main`), it can be activated
+with the given keystroke:
+
+~~~java
+FlatUIDefaultsInspector.install( "ctrl shift alt Y" );
+~~~
+
+![UI Defaults Inspector](../images/extras-FlatUIDefaultsInspector.png)