Method applyWatermark

processing/watermark.go:106–204

(
	ctx context.Context,
	img *vips.Image,
	po ProcessingOptions,
	offsetScale float64,
	framesCount int,
)

}

func (p *Processor) applyWatermark(
	ctx context.Context,
	img *vips.Image,
	po ProcessingOptions,
	offsetScale float64,
	framesCount int,
) error {
	if p.watermarkProvider == nil {
		return nil
	}

	wmData, _, err := p.watermarkProvider.Get(ctx, po.Options)
	if err != nil {
		return err
	}
	if wmData == nil {
		return nil
	}
	defer wmData.Close()

	wm := new(vips.Image)
	defer wm.Clear()

	width := img.Width()
	height := img.Height()
	frameHeight := height / framesCount

	if err := p.prepareWatermark(
		ctx, wm, wmData, po, width, frameHeight, offsetScale, framesCount,
	); err != nil {
		return err
	}

	opacity := po.WatermarkOpacity() * p.config.WatermarkOpacity

	position := po.WatermarkPosition()
	shouldReplicate := shouldReplicateWatermark(position)

	// If we replicated the watermark and need to apply it to an animated image,
	// it is faster to replicate the watermark to all the image and apply it single-pass
	if shouldReplicate && framesCount > 1 {
		if err := wm.Replicate(width, height, false); err != nil {
			return err
		}

		return img.ApplyWatermark(wm, 0, 0, opacity)
	}

	left, top := 0, 0
	wmWidth := wm.Width()
	wmHeight := wm.Height()

	if !shouldReplicate {
		gr := GravityOptions{
			Type: position,
			X:    po.WatermarkXOffset(),
			Y:    po.WatermarkYOffset(),
		}