adding field for text color to presentation_style

extensions/presentation.sigmf-ext.md

@@ -7,7 +7,8 @@ to help define how SigMF metadata should be presented graphically to users.
 All fields in the `presentation` extension are optional, thus any SigMF
 application using this extension is not required to implement any particular
 feature. It is RECOMMENDED that applications adhering to the `presentation`
-extension use default values in this document.
+extension use default values in this document. It is also RECOMMENDED that
+applications implementing this extension describe what fields are implemented.
 
 ## 0 Datatypes
 
@@ -80,6 +81,8 @@ the following form:
 |`line_color`|false|color|`#00ffffff`|Color of the foreground captures segment display features.|
 |`line_width`|false|double|1.0|Width of the line (in pixels) surrounding the annotation, fractional values are permitted.|
 |`fill_color`|false|color|`#ffffffff`|Color of the background, generally used with significant alpha.|
+|`text_color`|false|color|`#ffffffff`|Color of text rendered next to the annotation (label/comment fields, etc).|
+|`text_size`|false|double|8|Size (pt) of text rendered next to the annotation (label/comment fields, etc).|
 |`comment`|false|string||User comment field, any string is fine.|
 
 The `key` and `display_type` fields are required for all `presentation_style`
@@ -116,7 +119,7 @@ SigMF object:
 |name|required|type|default|description|
 |----|--------|----|-------|-----------|
 |`style`|false|[presentation style](presentation.sigmf-ext.md#the-presentation-style-field)|{}|Style to use for the annotation.|
-|`color`|false|`color`|`0x00ffffff`|Simple specification for the annotation box color.|
+|`color`|false|`color`|`0x00ffffff`|Simple suggestion for the annotation color, to be interpreted by the application.|
 
 The `color` and `style` fields SHOULD NOT both be provided. In the event of an
 overdetermined specification for color, the first specification found below
@@ -163,7 +166,8 @@ annotations above:
         "key": "VALID",
         "style": {
           "display_type": "none",
-          "comment": "Valid capture segments have no unique presentation."
+          "text_size": 0,
+          "comment": "Valid capture segments have no unique presentation, text disabled."
         }
       },
       {
@@ -172,8 +176,10 @@ annotations above:
           "display_type": "diagonal"
           "line_color": "#80ffff00",
           "line_width": "3.0",
+          "text_color": "#00ffff00",
+          "text_size": 18,
           "fill_color": "#c0000000",
-          "comment": "Invalid sections are shaded slightly grey with yellow diagonal lines."
+          "comment": "Invalid sections are shaded slightly grey with yellow diagonal lines and large, bright yellow text."
         }
       }
     ],