changes per US small group

Author: rwdougla

sources/modules/external/graphical-user-interfaces.md

@@ -11,7 +11,7 @@ _Specifies the different levels of teaching._
 ------------------------------------------------------------------------
 Level             Objective
 ----------------- ------------------------------------------------------
-Foundational:      Basic us of desktop graphical user interfaces
+Foundational:      Basic use of desktop graphical user interfaces
 
 Main:              Different forms of IO and accessibility
 
@@ -24,7 +24,7 @@ Advanced:          Internationalization and customization
 _Why is this important?_
 _Why do we want to learn/teach this topic?_
 
-For some applications a graphical user interface is beneficial. However, graphical user interfaces are not part of the C++ standard and external libraries are needed. We provide generic teaching goals and do not focus on a specific external library. Some mentionable libraries are: [Qt](https://www.qt.io/), [Cairo](https://www.cairographics.org/), and [wxWidgets](https://www.wxwidgets.org/). 
+For some applications a graphical user interface is beneficial. However, graphical user interfaces are not part of the C++ standard and external libraries are needed. We provide generic teaching goals and do not focus on a specific external library. Some mentionable platform-independent libraries are [Qt](https://www.qt.io/) and [wxWidgets](https://www.wxwidgets.org/) for interface development or [Cairo](https://www.cairographics.org/) and [OpenGL](https://www.opengl.org/) for graphics.
 
 ### Topic introduction
 
@@ -36,9 +36,9 @@ _Very brief introduction to the topic._
 
 A student: 
 
-1. should know linking libraries
-2. should know [header files](../compilation-model/headers.md)
-3. should know about [build systems](../compilation-model/buildsystems.md)
+1. should have a foundational knowledge of [linkage](../compilation-model/linkage.md)
+2. should have a foundational knowledge of [header files](../compilation-model/headers.md)
+3. should have a foundational knowledge of [build systems](../compilation-model/buildsystems.md)
 
 #### Student outcomes
 
@@ -48,32 +48,31 @@ _Max 5 items._
 
 A student should be able to:
 
-1. link against the external library
-2. write an application with one window
-3. add simple widgets like text boxes and buttons to the window
-4. catch events of buttons or other elements
-5. explain the mechanics of event-driven programming
+1. write an application with one window
+2. add simple widgets like text boxes and buttons to the window
+3. respond to events of buttons or other widgets
+4. explain the mechanics of event-driven programming
 
 #### Points to cover
 
 * use basic API functions
 * layout of the window
-* handle events by callbacks  
+* handle events by callbacks
 
 #### Caveats
 
 _This section mentions subtle points to understand, like anything resulting in
 implementation-defined, unspecified, or undefined behavior._
 
-* programming user interfaces in C++ and in general require plenty of boiler plate code  
+* programming user interfaces in C++ and in general require significant boiler plate code  
 * API calls are specific to one library and might not be transferable to other libraries
-* Some libraries are written in C 
+* some libraries are written in C or other languages
 
-### Main: Different forms of IO and accessibility
+### Main: Different forms of I/O and accessibility
 
 #### Background/Required Knowledge
 
-* All of the above.
+* all of the above
 
 #### Student outcomes
 
@@ -82,23 +81,27 @@ A student should be able to:
 1. add more advanced elements, like tables or images
 2. handle multiple windows
 3. show error and warning popups
-4. use different forms of IO, like keyboard, mouse, or touch pad
-5. explain basic of fonts and accessibility 
+4. use different forms of input and output (I/O), such as keyboard, mouse, or touch pad
+5. explain basics of fonts and accessibility
 
 #### Caveats
 
-*  programming user interfaces is rather complex and might not applicable for most students 
+* programming user interfaces is rather complex and might not be applicable for most students
 
 #### Points to cover
 
-* More advanced API calls and design patterns
+* more advanced API calls and design patterns
+* modal vs non-modal dialogs
 
 ### Advanced: Technicalities and tools
 
 _These are important topics that are not expected to be covered but provide
 guidance where one can continue to investigate this topic in more depth._
 
-* Internationalization
-* Font designers 
-* Hardware acceleration
-* Custom widget generation
+* internationalization
+* font designers 
+* hardware acceleration
+* custom widget generation
+* event-driven programming using non-UI elements, such as timers or sockets
+* multi-threaded user interface development
+