(feat): Add option to set max FPS (#578)

* (feat): add option for setting FPS on renderer

Co-authored-by: Christian Rocha <christian@rocha.is>

options.go

@@ -200,3 +200,12 @@ func WithFilter(filter func(Model, Msg) Msg) ProgramOption {
 		p.filter = filter
 	}
 }
+
+// WithMaxFPS sets a custom maximum FPS at which the renderer should run. If
+// less than 1, the default value of 60 will be used. If over 120, the FPS
+// will be capped at 120.
+func WithFPS(fps int) ProgramOption {
+	return func(p *Program) {
+		p.fps = fps
+	}
+}

standard_renderer.go

@@ -16,7 +16,8 @@ import (
 const (
 	// defaultFramerate specifies the maximum interval at which we should
 	// update the view.
-	defaultFramerate = time.Second / 60
+	defaultFPS = 60
+	maxFPS     = 120
 )
 
 // standardRenderer is a framerate-based terminal renderer, updating the view
@@ -54,12 +55,17 @@ type standardRenderer struct {
 
 // newRenderer creates a new renderer. Normally you'll want to initialize it
 // with os.Stdout as the first argument.
-func newRenderer(out *termenv.Output, useANSICompressor bool) renderer {
+func newRenderer(out *termenv.Output, useANSICompressor bool, fps int) renderer {
+	if fps < 1 {
+		fps = defaultFPS
+	} else if fps > maxFPS {
+		fps = maxFPS
+	}
 	r := &standardRenderer{
 		out:                out,
 		mtx:                &sync.Mutex{},
 		done:               make(chan struct{}),
-		framerate:          defaultFramerate,
+		framerate:          time.Second / time.Duration(fps),
 		useANSICompressor:  useANSICompressor,
 		queuedMessageLines: []string{},
 	}

tea.go

@@ -144,6 +144,10 @@ type Program struct {
 	windowsStdin *os.File //nolint:golint,structcheck,unused
 
 	filter func(Model, Msg) Msg
+
+	// fps is the frames per second we should set on the renderer, if
+	// applicable,
+	fps int
 }
 
 // Quit is a special command that tells the Bubble Tea program to exit.
@@ -445,7 +449,7 @@ func (p *Program) Run() (Model, error) {
 
 	// If no renderer is set use the standard one.
 	if p.renderer == nil {
-		p.renderer = newRenderer(p.output, p.startupOptions.has(withANSICompressor))
+		p.renderer = newRenderer(p.output, p.startupOptions.has(withANSICompressor), p.fps)
 	}
 
 	// Check if output is a TTY before entering raw mode, hiding the cursor and