Add "text" display element

Signed-off-by: Knut Ahlers <knut@ahlers.me>

cmd/streamdeck/display_exec.go

@@ -47,7 +47,7 @@ func (d displayElementExec) Display(ctx context.Context, idx int, attributes map
 	}
 
 	// Execute command and parse it
-	var buf = new(bytes.Buffer)
+	buf := new(bytes.Buffer)
 
 	processEnv := env.ListToMap(os.Environ())
 
@@ -120,7 +120,7 @@ func (d displayElementExec) Display(ctx context.Context, idx int, attributes map
 		fontsize = v
 	}
 
-	var border = 10
+	border := 10
 	if v, ok := attributes["border"].(int); ok {
 		border = v
 	}
@@ -160,7 +160,7 @@ func (d displayElementExec) NeedsLoop(attributes map[string]interface{}) bool {
 func (d *displayElementExec) StartLoopDisplay(ctx context.Context, idx int, attributes map[string]interface{}) error {
 	d.running = true
 
-	var interval = 5 * time.Second
+	interval := 5 * time.Second
 	if v, ok := attributes["interval"].(int); ok {
 		interval = time.Duration(v) * time.Second
 	}

cmd/streamdeck/display_text.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"context"
+	"github.com/pkg/errors"
+	"image/color"
+	_ "image/jpeg"
+	_ "image/png"
+	"strings"
+)
+
+func init() {
+	registerDisplayElement("text", &displayElementText{})
+}
+
+type displayElementText struct {
+	running bool
+}
+
+func (d displayElementText) Display(ctx context.Context, idx int, attributes map[string]interface{}) error {
+	var (
+		err         error
+		imgRenderer = newTextOnImageRenderer()
+	)
+
+	// Initialize background
+	if filename, ok := attributes["image"].(string); ok {
+		if err = imgRenderer.DrawBackgroundFromFile(filename); err != nil {
+			return errors.Wrap(err, "Unable to draw background from disk")
+		}
+	}
+
+	// Initialize color
+	var textColor color.Color = color.RGBA{0xff, 0xff, 0xff, 0xff}
+	if rgba, ok := attributes["color"].([]interface{}); ok {
+		if len(rgba) != 4 {
+			return errors.New("RGBA color definition needs 4 hex values")
+		}
+
+		tmpCol := color.RGBA{}
+
+		for cidx, vp := range []*uint8{&tmpCol.R, &tmpCol.G, &tmpCol.B, &tmpCol.A} {
+			switch rgba[cidx].(type) {
+			case int:
+				*vp = uint8(rgba[cidx].(int))
+			case float64:
+				*vp = uint8(rgba[cidx].(float64))
+			}
+		}
+
+		textColor = tmpCol
+	}
+
+	// Initialize fontsize
+	var fontsize float64 = 120
+	if v, ok := attributes["font_size"].(float64); ok {
+		fontsize = v
+	}
+
+	border := 10
+	if v, ok := attributes["border"].(int); ok {
+		border = v
+	}
+
+	if strings.TrimSpace(attributes["text"].(string)) != "" {
+		if err = imgRenderer.DrawBigText(strings.TrimSpace(attributes["text"].(string)), fontsize, border, textColor); err != nil {
+			return errors.Wrap(err, "Unable to render text")
+		}
+	}
+
+	if caption, ok := attributes["caption"].(string); ok && strings.TrimSpace(caption) != "" {
+		if err = imgRenderer.DrawCaptionText(strings.TrimSpace(caption)); err != nil {
+			return errors.Wrap(err, "Unable to render caption")
+		}
+	}
+
+	if !d.running && d.NeedsLoop(attributes) {
+		return nil
+	}
+
+	if err := ctx.Err(); err != nil {
+		// Page context was cancelled, do not draw
+		return err
+	}
+
+	return errors.Wrap(sd.FillImage(idx, imgRenderer.GetImage()), "Unable to set image")
+}
+
+func (d displayElementText) NeedsLoop(attributes map[string]interface{}) bool { return false }