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62 lines
2.2 KiB
62 lines
2.2 KiB
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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"""
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addimage.py
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Add a PNG image to a frame
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History:
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--------
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25.05.20/KQ Initial (modularized) version
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27.05.20/KQ Variable naming corrected
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"""
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import numpy as np
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import cv2
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import sys
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# My own new version w/ transparency effect (& reasonable performance)
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def overlay_png(frame, x_offset, y_offset, png, alpha_mask):
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"""Overlay a png on an OpenCV frame @x_offset/y_offset w/ transparency effect based on png alpha channel
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"""
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_scr_height = png.shape[0]
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_scr_width = png.shape[1]
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_frame_roi = frame[y_offset:y_offset+_scr_height, x_offset:x_offset+_scr_width, 0:3] # Source original region
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_all_square_bg_fg = cv2.bitwise_or(_frame_roi >> 2, png, mask=alpha_mask) # Both added, background somewhat reduced ...
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_mask_inv = cv2.bitwise_not(alpha_mask) # Negate mask (inverse)
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_surrounding_bg = cv2.bitwise_or(_frame_roi, png, mask=_mask_inv) # This yields the original background at transparent regions
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frame[y_offset:y_offset+_scr_height, x_offset:x_offset+_scr_width, 0:3] = _all_square_bg_fg + _surrounding_bg # Now add both: Transparent add achieved!
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# Ref.: https://stackoverflow.com/questions/14063070/overlay-a-smaller-image-on-a-larger-image-python-opencv
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def overlay_image_alpha(img, img_overlay, pos, alpha_mask):
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"""Overlay img_overlay on top of img at the position specified by
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pos and blend using alpha_mask.
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Alpha mask must contain values within the range [0, 1] and be the
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same size as img_overlay.
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"""
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x, y = pos
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# Image ranges
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y1, y2 = max(0, y), min(img.shape[0], y + img_overlay.shape[0])
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x1, x2 = max(0, x), min(img.shape[1], x + img_overlay.shape[1])
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# Overlay ranges
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y1o, y2o = max(0, -y), min(img_overlay.shape[0], img.shape[0] - y)
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x1o, x2o = max(0, -x), min(img_overlay.shape[1], img.shape[1] - x)
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# Exit if nothing to do
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if y1 >= y2 or x1 >= x2 or y1o >= y2o or x1o >= x2o:
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return
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channels = img.shape[2]
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alpha = alpha_mask[y1o:y2o, x1o:x2o] # Alpha channel only: 0..1 where <>0 means NOT transparent!
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alpha_inv = 1.0 - alpha
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for c in range(channels):
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img[y1:y2, x1:x2, c] = (alpha * img_overlay[y1o:y2o, x1o:x2o, c] +
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alpha_inv * img[y1:y2, x1:x2, c])
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