Fix step wise resolutions in linux camera

Some cameras support a range of resolutions with step wise. The fix is
to not only capture the highest resolutions but uses the step wise to
determine if we can support the hardcoded standard resolutions,
https://commons.wikimedia.org/wiki/File:Vector_Video_Standards2.svg.
In the future, we should use a custom data structure to capture more
resolutions that are outside of the listed standard resolutions.

pkg/driver/camera/camera_linux.go

@@ -26,6 +26,36 @@ const (
 var (
 	errReadTimeout = errors.New("read timeout")
 	errEmptyFrame  = errors.New("empty frame")
+	// Reference: https://commons.wikimedia.org/wiki/File:Vector_Video_Standards2.svg
+	supportedResolutions = [][2]int{
+		{320, 240},
+		{640, 480},
+		{768, 576},
+		{800, 600},
+		{1024, 768},
+		{1280, 854},
+		{1280, 960},
+		{1280, 1024},
+		{1400, 1050},
+		{1600, 1200},
+		{2048, 1536},
+		{320, 200},
+		{800, 480},
+		{854, 480},
+		{1024, 600},
+		{1152, 768},
+		{1280, 720},
+		{1280, 768},
+		{1366, 768},
+		{1280, 800},
+		{1440, 900},
+		{1440, 960},
+		{1680, 1050},
+		{1920, 1080},
+		{2048, 1080},
+		{1920, 1200},
+		{2560, 1600},
+	}
 )
 
 // Camera implementation using v4l2
@@ -212,13 +242,41 @@ func (c *camera) Properties() []prop.Media {
 				continue
 			}
 
-			properties = append(properties, prop.Media{
-				Video: prop.Video{
-					Width:       int(frameSize.MaxWidth),
-					Height:      int(frameSize.MaxHeight),
-					FrameFormat: supportedFormat,
-				},
-			})
+			if frameSize.StepWidth == 0 || frameSize.StepHeight == 0 {
+				properties = append(properties, prop.Media{
+					Video: prop.Video{
+						Width:       int(frameSize.MaxWidth),
+						Height:      int(frameSize.MaxHeight),
+						FrameFormat: supportedFormat,
+					},
+				})
+			} else {
+				// FIXME: we should probably use a custom data structure to capture all of the supported resolutions
+				for _, supportedResolution := range supportedResolutions {
+					minWidth, minHeight := int(frameSize.MinWidth), int(frameSize.MinHeight)
+					maxWidth, maxHeight := int(frameSize.MaxWidth), int(frameSize.MaxHeight)
+					stepWidth, stepHeight := int(frameSize.StepWidth), int(frameSize.StepHeight)
+					width, height := supportedResolution[0], supportedResolution[1]
+
+					if width < minWidth || width > maxWidth ||
+						height < minHeight || height > maxHeight {
+						continue
+					}
+
+					if (width-minWidth)%stepWidth != 0 ||
+						(height-minHeight)%stepHeight != 0 {
+						continue
+					}
+
+					properties = append(properties, prop.Media{
+						Video: prop.Video{
+							Width:       width,
+							Height:      height,
+							FrameFormat: supportedFormat,
+						},
+					})
+				}
+			}
 		}
 	}
 	return properties