Added page up/down features

cursor.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+    "math"
 	ui "github.com/gizak/termui"
 )
 
@@ -130,3 +131,48 @@ func (gc *GridCursor) Down() {
 	gc.ScrollPage()
 	ui.Render(cGrid)
 }
+
+func (gc *GridCursor) PgUp() {
+    idx := gc.Idx()
+	if idx <= 0 { // already at top
+		return
+	}
+
+	var nextidx int
+	nextidx = int(math.Max(0.0, float64(idx - cGrid.MaxRows())))
+	cGrid.Offset = int(math.Max(float64(cGrid.Offset - cGrid.MaxRows()),
+		float64(0)))
+
+	active := gc.filtered[idx]
+	next   := gc.filtered[nextidx]
+
+	active.Widgets.Name.UnHighlight()
+	gc.selectedID = next.Id
+	next.Widgets.Name.Highlight()
+	
+	cGrid.Align()
+	ui.Render(cGrid)
+}
+
+func (gc *GridCursor) PgDown() {
+    idx := gc.Idx()
+	if idx >= gc.Len()-1 { // already at bottom
+		return
+	}
+
+	var nextidx int
+	nextidx = int(math.Min(float64(gc.Len() - 1),
+		float64(idx + cGrid.MaxRows())))
+	cGrid.Offset = int(math.Min(float64(cGrid.Offset + cGrid.MaxRows()),
+		float64(gc.Len() - cGrid.MaxRows())))
+
+	active := gc.filtered[idx]
+	next   := gc.filtered[nextidx]
+
+	active.Widgets.Name.UnHighlight()
+	gc.selectedID = next.Id
+	next.Widgets.Name.Highlight()
+
+	cGrid.Align()
+	ui.Render(cGrid)
+}

grid.go

@@ -79,6 +79,10 @@ func Display() bool {
 
 	HandleKeys("up", cursor.Up)
 	HandleKeys("down", cursor.Down)
+
+	HandleKeys("pgup", cursor.PgUp)
+	HandleKeys("pgdown", cursor.PgDown)
+
 	HandleKeys("exit", ui.StopLoop)
 	HandleKeys("help", func() {
 		menu = HelpMenu

keys.go

@@ -4,6 +4,7 @@ import (
 	ui "github.com/gizak/termui"
 )
 
+// Common action keybindings
 // Common action keybindings
 var keyMap = map[string][]string{
 	"up": []string{
@@ -14,6 +15,14 @@ var keyMap = map[string][]string{
 		"/sys/kbd/<down>",
 		"/sys/kbd/j",
 	},
+	"pgup": []string{
+		"/sys/kbd/<previous>",
+		"/sys/kbd/C-<up>",
+	},
+	"pgdown": []string{
+		"/sys/kbd/<next>",
+		"/sys/kbd/C-<down>",
+    },
 	"exit": []string{
 		"/sys/kbd/q",
 		"/sys/kbd/C-c",