Add button caption rendering

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

cmd/streamdeck/config.go

@@ -1,9 +1,16 @@
 package main
 
-import "time"
+import (
+	"time"
+)
 
 type config struct {
 	AutoReload        bool            `yaml:"auto_reload"`
+	CaptionBorder     int             `yaml:"caption_border"`
+	CaptionColor      [4]int          `yaml:"caption_color"`
+	CaptionFont       string          `yaml:"caption_font"`
+	CaptionFontSize   float64         `yaml:"caption_font_size"`
+	CaptionPosition   captionPosition `yaml:"caption_position"`
 	DefaultBrightness int             `yaml:"default_brightness"`
 	DefaultPage       string          `yaml:"default_page"`
 	DisplayOffTime    time.Duration   `yaml:"display_off_time"`
@@ -31,3 +38,10 @@ func newConfig() config {
 		AutoReload: true,
 	}
 }
+
+type captionPosition string
+
+const (
+	captionPositionBottom = "bottom"
+	captionPositionTop    = "top"
+)

cmd/streamdeck/display_exec.go

@@ -131,6 +131,12 @@ func (d displayElementExec) Display(ctx context.Context, idx int, attributes map
 		}
 	}
 
+	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
 	}

cmd/streamdeck/display_pulsevolume.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"fmt"
 	"image/color"
+	"strings"
 	"time"
 
 	"github.com/pkg/errors"
@@ -112,6 +113,12 @@ func (d displayElementPulseVolume) Display(ctx context.Context, idx int, attribu
 		return errors.Wrap(err, "Unable to draw text")
 	}
 
+	if caption, ok := attributes["caption"].(string); ok && strings.TrimSpace(caption) != "" {
+		if err = img.DrawCaptionText(strings.TrimSpace(caption)); err != nil {
+			return errors.Wrap(err, "Unable to render caption")
+		}
+	}
+
 	if err = ctx.Err(); err != nil {
 		// Page context was cancelled, do not draw
 		return err

cmd/streamdeck/helper_displayText.go

@@ -15,6 +15,14 @@ import (
 	"golang.org/x/image/math/fixed"
 )
 
+type textDrawAnchor uint
+
+const (
+	textDrawAnchorCenter textDrawAnchor = iota
+	textDrawAnchorBottom
+	textDrawAnchorTop
+)
+
 type textOnImageRenderer struct {
 	img draw.Image
 }
@@ -46,7 +54,7 @@ func (t *textOnImageRenderer) DrawBackgroundFromFile(filename string) error {
 
 func (t *textOnImageRenderer) DrawBigText(text string, fontSizeHint float64, border int, textColor color.Color) error {
 	// Render text
-	f, err := t.loadFont()
+	f, err := t.loadFont(userConfig.RenderFont)
 	if err != nil {
 		return errors.Wrap(err, "Unable to load font")
 	}
@@ -58,12 +66,44 @@ func (t *textOnImageRenderer) DrawBigText(text string, fontSizeHint float64, bor
 	c.SetFont(f)
 	c.SetHinting(font.HintingNone)
 
-	return t.drawText(c, text, textColor, fontSizeHint, border)
+	return t.drawText(c, text, textColor, fontSizeHint, border, textDrawAnchorCenter)
+}
+
+func (t *textOnImageRenderer) DrawCaptionText(text string) error {
+	// Render text
+	f, err := t.loadFont(userConfig.CaptionFont)
+	if err != nil {
+		return errors.Wrap(err, "Unable to load font")
+	}
+
+	var textColor color.Color = color.RGBA{0xff, 0xff, 0xff, 0xff}
+	if userConfig.CaptionColor[3] != 0x0 {
+		textColor = color.RGBA{
+			uint8(userConfig.CaptionColor[0]),
+			uint8(userConfig.CaptionColor[1]),
+			uint8(userConfig.CaptionColor[2]),
+			uint8(userConfig.CaptionColor[3]),
+		}
+	}
+
+	var anchor = textDrawAnchorBottom
+	if userConfig.CaptionPosition == "top" {
+		anchor = textDrawAnchorTop
+	}
+
+	c := freetype.NewContext()
+	c.SetClip(t.img.Bounds())
+	c.SetDPI(72)
+	c.SetDst(t.img)
+	c.SetFont(f)
+	c.SetHinting(font.HintingNone)
+
+	return t.drawText(c, text, textColor, userConfig.CaptionFontSize, userConfig.CaptionBorder, anchor)
 }
 
 func (t textOnImageRenderer) GetImage() image.Image { return t.img }
 
-func (t *textOnImageRenderer) drawText(c *freetype.Context, text string, textColor color.Color, fontsize float64, border int) error {
+func (t *textOnImageRenderer) drawText(c *freetype.Context, text string, textColor color.Color, fontsize float64, border int, anchor textDrawAnchor) error {
 	c.SetSrc(image.NewUniform(color.RGBA{0x0, 0x0, 0x0, 0x0})) // Transparent for text size guessing
 
 	textLines := strings.Split(text, "\n")
@@ -92,9 +132,18 @@ func (t *textOnImageRenderer) drawText(c *freetype.Context, text string, textCol
 
 	var (
 		yTotal   = (int(c.PointToFixed(fontsize)/64))*len(textLines) + (len(textLines)-1)*2
-		yLineTop = int(float64(sd.IconSize())/2.0 - float64(yTotal)/2.0)
+		yLineTop int
 	)
 
+	switch anchor {
+	case textDrawAnchorTop:
+		yLineTop = border
+	case textDrawAnchorCenter:
+		yLineTop = int(float64(sd.IconSize())/2.0 - float64(yTotal)/2.0)
+	case textDrawAnchorBottom:
+		yLineTop = sd.IconSize() - yTotal - border
+	}
+
 	for _, tl := range textLines {
 		c.SetSrc(image.NewUniform(color.RGBA{0x0, 0x0, 0x0, 0x0})) // Transparent for text size guessing
 		ext, err := c.DrawString(tl, freetype.Pt(0, 0))
@@ -132,8 +181,8 @@ func (textOnImageRenderer) getImageFromDisk(filename string) (image.Image, error
 	return img, nil
 }
 
-func (textOnImageRenderer) loadFont() (*truetype.Font, error) {
+func (textOnImageRenderer) loadFont(fontfile string) (*truetype.Font, error) {
-	fontRaw, err := ioutil.ReadFile(userConfig.RenderFont)
+	fontRaw, err := ioutil.ReadFile(fontfile)
 	if err != nil {
 		return nil, errors.Wrap(err, "Unable to read font file")
 	}