text overlay x & y pos as params

cmd/mxl-pattern/main.go

@@ -31,7 +31,10 @@ type appArgs struct {
 	audioFlowDefFile string
 	pattern          string
 	listPatterns     bool
-	textOverlay      string
+
+	textOverlay string
+	overlayX    int
+	overlayY    int
 
 	videoWidth  uint
 	videoHeight uint
@@ -249,7 +252,11 @@ func flagSetAddFlags(fs *pflag.FlagSet, args *appArgs) {
 	// Video pattern flags
 	fs.StringVarP(&args.pattern, "pattern", "p", "bars", "Video pattern type")
 	fs.BoolVar(&args.listPatterns, "list-patterns", false, "List video available video patterns and exit")
+
 	fs.StringVarP(&args.textOverlay, "text", "t", "", "Text overlay above video pattern")
+	fs.IntVar(&args.overlayX, "text-x", 0, "Text overlay X position in px")
+	fs.IntVar(&args.overlayY, "text-y", 0, "Text overlay Y position in px")
+
 	fs.UintVar(&args.videoWidth, "width", 1920, "Video pattern width")
 	fs.UintVar(&args.videoHeight, "height", 1080, "Video pattern height")
 	fs.StringVar(&args.videoFPS, "fps", "25", "Video pattern FPS")
@@ -341,7 +348,20 @@ func main() {
 			log.Fatalf("text overlay init failed: %v", err)
 		}
 		defer face.Close()
-		overlay, err = generator.NewTextOverlay(args.textOverlay, int(vi.width), int(vi.height), face)
+		if args.overlayX < 0 ||
+			args.overlayX > int(vi.width) ||
+			args.overlayY < 0 ||
+			args.overlayY > int(vi.height) {
+			log.Fatalf("Overlay X/Y pos can't be negative or greater, than video width/height")
+		}
+		overlay, err = generator.NewTextOverlay(
+			args.textOverlay,
+			int(vi.width),
+			int(vi.height),
+			args.overlayX,
+			args.overlayY,
+			face,
+		)
 		if err != nil {
 			log.Fatalf("text overlay init failed: %v", err)
 		}

internal/generator/text.go

@@ -48,7 +48,7 @@ func LoadFace(path string, size float64) (font.Face, error) {
 // NewTextOverlay rasterizes text (white, anti-aliased) onto a black backing
 // box, centered horizontally. Box width and x are multiples of 6 so the box
 // covers whole v210 blocks and the per-frame copy is word-aligned.
-func NewTextOverlay(text string, frameW, frameH int, face font.Face) (*TextOverlay, error) {
+func NewTextOverlay(text string, frameW, frameH, posX, posY int, face font.Face) (*TextOverlay, error) {
 	if text == "" {
 		return nil, fmt.Errorf("text: empty string")
 	}
@@ -89,10 +89,12 @@ func NewTextOverlay(text string, frameW, frameH int, face font.Face) (*TextOverl
 		return nil, fmt.Errorf("text: box %dpx does not fit frame height %dpx", topMargin+h, frameH)
 	}
 
+	// posX = ((frameW - w) / 2 / 6) * 6
+	// posY = topMargin
 	o := &TextOverlay{
 		frameW: frameW,
-		x:      ((frameW - w) / 2 / 6) * 6,
-		y:      topMargin,
+		x:      posX,
+		y:      posY,
 		w:      w,
 		h:      h,
 		cov:    make([]byte, w*h),