I am trying to create scrollbars in a window created by OpenCv python. Specifically, I want merge this HSV scroll bar code in the answer (1) (Choosing the correct upper and lower HSV boundaries for color detection with`cv::inRange` (OpenCV)) with this zoom in zoom out scroll bar code in the answer (2) (Creating trackbars to scroll large image in OpenCV Python). Both working separately, but I would like to use them in the same window.
def nothing(x):
pass
# Load image
image = cv2.imread("XXX.jpg")
# Create a window
cv2.namedWindow('image')
# Resize a window
cv2.resizeWindow('image', 1,1)
# Create trackbars for color change
# Hue is from 0-179 for Opencv
cv2.createTrackbar('HMin', 'image', 0, 179, nothing)
cv2.createTrackbar('SMin', 'image', 0, 255, nothing)
cv2.createTrackbar('VMin', 'image', 0, 255, nothing)
cv2.createTrackbar('HMax', 'image', 0, 179, nothing)
cv2.createTrackbar('SMax', 'image', 0, 255, nothing)
cv2.createTrackbar('VMax', 'image', 0, 255, nothing)
# Set default value for Max HSV trackbars
cv2.setTrackbarPos('HMax', 'image', 179)
cv2.setTrackbarPos('SMax', 'image', 255)
cv2.setTrackbarPos('VMax', 'image', 255)
# Initialize HSV min/max values
hMin = sMin = vMin = hMax = sMax = vMax = 0
phMin = psMin = pvMin = phMax = psMax = pvMax = 0
while(1):
# Get current positions of all trackbars
hMin = cv2.getTrackbarPos('HMin', 'image')
sMin = cv2.getTrackbarPos('SMin', 'image')
vMin = cv2.getTrackbarPos('VMin', 'image')
hMax = cv2.getTrackbarPos('HMax', 'image')
sMax = cv2.getTrackbarPos('SMax', 'image')
vMax = cv2.getTrackbarPos('VMax', 'image')
# Set minimum and maximum HSV values to display
lower = np.array([hMin, sMin, vMin])
upper = np.array([hMax, sMax, vMax])
# Convert to HSV format and color threshold
hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)
mask = cv2.inRange(hsv, lower, upper)
result = cv2.bitwise_and(image, image, mask=mask)
# Print if there is a change in HSV value
if((phMin != hMin) | (psMin != sMin) | (pvMin != vMin) | (phMax != hMax) | (psMax != sMax) | (pvMax != vMax) ):
print("(hMin = %d , sMin = %d, vMin = %d), (hMax = %d , sMax = %d, vMax = %d)" % (hMin , sMin , vMin, hMax, sMax , vMax))
phMin = hMin
psMin = sMin
pvMin = vMin
phMax = hMax
psMax = sMax
pvMax = vMax
# Display result image
cv2.imshow('image', result)
if cv2.waitKey(10) & 0xFF == ord('q'):
break
Code (2) Creating trackbars to scroll large image in OpenCV Python
# -*- coding: utf-8 -*-
import cv2
import numpy as np
class PanZoomWindow(object):
""" Controls an OpenCV window. Registers a mouse listener so that:
1. right-dragging up/down zooms in/out
2. right-clicking re-centers
3. trackbars scroll vertically and horizontally
You can open multiple windows at once if you specify different window names.
You can pass in an onLeftClickFunction, and when the user left-clicks, this
will call onLeftClickFunction(y,x), with y,x in original image coordinates."""
def __init__(self, img, windowName = 'PanZoomWindow', onLeftClickFunction = None):
self.WINDOW_NAME = windowName
self.H_TRACKBAR_NAME = 'x'
self.V_TRACKBAR_NAME = 'y'
self.img = img
self.onLeftClickFunction = onLeftClickFunction
self.TRACKBAR_TICKS = 1000
self.panAndZoomState = PanAndZoomState(img.shape, self)
self.lButtonDownLoc = None
self.mButtonDownLoc = None
self.rButtonDownLoc = None
cv2.namedWindow(self.WINDOW_NAME, cv2.WINDOW_NORMAL)
self.redrawImage()
cv2.setMouseCallback(self.WINDOW_NAME, self.onMouse)
cv2.createTrackbar(self.H_TRACKBAR_NAME, self.WINDOW_NAME, 0, self.TRACKBAR_TICKS, self.onHTrackbarMove)
cv2.createTrackbar(self.V_TRACKBAR_NAME, self.WINDOW_NAME, 0, self.TRACKBAR_TICKS, self.onVTrackbarMove)
def onMouse(self,event, x,y,_ignore1,_ignore2):
""" Responds to mouse events within the window.
The x and y are pixel coordinates in the image currently being displayed.
If the user has zoomed in, the image being displayed is a sub-region, so you'll need to
add self.panAndZoomState.ul to get the coordinates in the full image."""
if event == cv2.EVENT_MOUSEMOVE:
return
elif event == cv2.EVENT_RBUTTONDOWN:
#record where the user started to right-drag
self.mButtonDownLoc = np.array([y,x])
elif event == cv2.EVENT_RBUTTONUP and self.mButtonDownLoc is not None:
#the user just finished right-dragging
dy = y - self.mButtonDownLoc[0]
pixelsPerDoubling = 0.2*self.panAndZoomState.shape[0] #lower = zoom more
changeFactor = (1.0+abs(dy)/pixelsPerDoubling)
changeFactor = min(max(1.0,changeFactor),5.0)
if changeFactor < 1.05:
dy = 0 #this was a click, not a draw. So don't zoom, just re-center.
if dy > 0: #moved down, so zoom out.
zoomInFactor = 1.0/changeFactor
else:
zoomInFactor = changeFactor
# print("zoomFactor: %s"%zoomFactor)
self.panAndZoomState.zoom(self.mButtonDownLoc[0], self.mButtonDownLoc[1], zoomInFactor)
elif event == cv2.EVENT_LBUTTONDOWN:
#the user pressed the left button.
coordsInDisplayedImage = np.array([y,x])
if np.any(coordsInDisplayedImage < 0) or np.any(coordsInDisplayedImage > self.panAndZoomState.shape[:2]):
print("you clicked outside the image area")
else:
print("you clicked on %s within the zoomed rectangle"%coordsInDisplayedImage)
coordsInFullImage = self.panAndZoomState.ul + coordsInDisplayedImage
print("this is %s in the actual image"%coordsInFullImage)
print("this pixel holds %s, %s"%(self.img[coordsInFullImage[0],coordsInFullImage[1]]))
if self.onLeftClickFunction is not None:
self.onLeftClickFunction(coordsInFullImage[0],coordsInFullImage[1])
#you can handle other mouse click events here
def onVTrackbarMove(self,tickPosition):
self.panAndZoomState.setYFractionOffset(float(tickPosition)/self.TRACKBAR_TICKS)
def onHTrackbarMove(self,tickPosition):
self.panAndZoomState.setXFractionOffset(float(tickPosition)/self.TRACKBAR_TICKS)
def redrawImage(self):
pzs = self.panAndZoomState
cv2.imshow(self.WINDOW_NAME, self.img[pzs.ul[0]:pzs.ul[0]+pzs.shape[0], pzs.ul[1]:pzs.ul[1]+pzs.shape[1]])
class PanAndZoomState(object):
""" Tracks the currently-shown rectangle of the image.
Does the math to adjust this rectangle to pan and zoom."""
MIN_SHAPE = np.array([50,50])
def __init__(self, imShape, parentWindow):
self.ul = np.array([0,0]) #upper left of the zoomed rectangle (expressed as y,x)
self.imShape = np.array(imShape[0:2])
self.shape = self.imShape #current dimensions of rectangle
self.parentWindow = parentWindow
def zoom(self,relativeCy,relativeCx,zoomInFactor):
self.shape = (self.shape.astype(np.float)/zoomInFactor).astype(np.int)
#expands the view to a square shape if possible. (I don't know how to get the actual window aspect ratio)
self.shape[:] = np.max(self.shape)
self.shape = np.maximum(PanAndZoomState.MIN_SHAPE,self.shape) #prevent zooming in too far
c = self.ul+np.array([relativeCy,relativeCx])
self.ul = (c-self.shape/2).astype(np.int)
self._fixBoundsAndDraw()
def _fixBoundsAndDraw(self):
""" Ensures we didn't scroll/zoom outside the image.
Then draws the currently-shown rectangle of the image."""
# print("in self.ul: %s shape: %s"%(self.ul,self.shape))
self.ul = np.maximum(0,np.minimum(self.ul, self.imShape-self.shape))
self.shape = np.minimum(np.maximum(PanAndZoomState.MIN_SHAPE,self.shape), self.imShape-self.ul)
# print("out self.ul: %s shape: %s"%(self.ul,self.shape))
yFraction = float(self.ul[0])/max(1,self.imShape[0]-self.shape[0])
xFraction = float(self.ul[1])/max(1,self.imShape[1]-self.shape[1])
cv2.setTrackbarPos(self.parentWindow.H_TRACKBAR_NAME, self.parentWindow.WINDOW_NAME,int(xFraction*self.parentWindow.TRACKBAR_TICKS))
cv2.setTrackbarPos(self.parentWindow.V_TRACKBAR_NAME, self.parentWindow.WINDOW_NAME,int(yFraction*self.parentWindow.TRACKBAR_TICKS))
self.parentWindow.redrawImage()
def setYAbsoluteOffset(self,yPixel):
self.ul[0] = min(max(0,yPixel), self.imShape[0]-self.shape[0])
self._fixBoundsAndDraw()
def setXAbsoluteOffset(self,xPixel):
self.ul[1] = min(max(0,xPixel), self.imShape[1]-self.shape[1])
self._fixBoundsAndDraw()
def setYFractionOffset(self,fraction):
""" pans so the upper-left zoomed rectange is "fraction" of the way down the image."""
self.ul[0] = int(round((self.imShape[0]-self.shape[0])*fraction))
self._fixBoundsAndDraw()
def setXFractionOffset(self,fraction):
""" pans so the upper-left zoomed rectange is "fraction" of the way right on the image."""
self.ul[1] = int(round((self.imShape[1]-self.shape[1])*fraction))
self._fixBoundsAndDraw()
if __name__ == "__main__":
infile = "XXX.jpg"
myImage = cv2.imread(infile,cv2.IMREAD_ANYCOLOR)
window = PanZoomWindow(myImage, "test window")
key = -1
while key != ord('q') and key != 27: # 27 = escape key
#the OpenCV window won't display until you call cv2.waitKey()
key = cv2.waitKey(5) #User can press 'q' or ESC to exit.
cv2.destroyAllWindows()
