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Doxygen tutorials: python final edits

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Maksim Shabunin
2014-12-01 15:46:05 +03:00
parent 875f922332
commit 812ce48c36
49 changed files with 426 additions and 353 deletions
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doc/py_tutorials/py_gui/py_image_display/py_image_display.markdown
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@@ -23,8 +23,9 @@ Second argument is a flag which specifies the way image should be read.
- cv2.IMREAD_GRAYSCALE : Loads image in grayscale mode
- cv2.IMREAD_UNCHANGED : Loads image as such including alpha channel
@note Instead of these three flags, you can simply pass integers 1, 0 or -1 respectively. See the
code below:
@note Instead of these three flags, you can simply pass integers 1, 0 or -1 respectively.
See the code below:
@code{.py}
import numpy as np
import cv2
@@ -32,6 +33,7 @@ import cv2
# Load an color image in grayscale
img = cv2.imread('messi5.jpg',0)
@endcode
**warning**
Even if the image path is wrong, it won't throw any error, but print img will give you None
@@ -58,15 +60,19 @@ the program continues. If **0** is passed, it waits indefinitely for a key strok
set to detect specific key strokes like, if key a is pressed etc which we will discuss below.
@note Besides binding keyboard events this function also processes many other GUI events, so you
MUST use it to actually display the image. **cv2.destroyAllWindows()** simply destroys all the
windows we created. If you want to destroy any specific window, use the function
**cv2.destroyWindow()** where you pass the exact window name as the argument.
MUST use it to actually display the image.
**cv2.destroyAllWindows()** simply destroys all the windows we created. If you want to destroy any
specific window, use the function **cv2.destroyWindow()** where you pass the exact window name as
the argument.
@note There is a special case where you can already create a window and load image to it later. In
that case, you can specify whether window is resizable or not. It is done with the function
**cv2.namedWindow()**. By default, the flag is cv2.WINDOW_AUTOSIZE. But if you specify flag to be
cv2.WINDOW_NORMAL, you can resize window. It will be helpful when image is too large in dimension
and adding track bar to windows. See the code below:
and adding track bar to windows.
See the code below:
@code{.py}
cv2.namedWindow('image', cv2.WINDOW_NORMAL)
cv2.imshow('image',img)
@@ -100,6 +106,7 @@ elif k == ord('s'): # wait for 's' key to save and exit
cv2.imwrite('messigray.png',img)
cv2.destroyAllWindows()
@endcode
**warning**
If you are using a 64-bit machine, you will have to modify k = cv2.waitKey(0) line as follows :
@@ -126,9 +133,13 @@ A screen-shot of the window will look like this :
![image](images/matplotlib_screenshot.jpg)
@sa Plenty of plotting options are available in Matplotlib. Please refer to Matplotlib docs for more
details. Some, we will see on the way. .. warning:: Color image loaded by OpenCV is in BGR mode. But
Matplotlib displays in RGB mode. So color images will not be displayed correctly in Matplotlib if
image is read with OpenCV. Please see the exercises for more details.
details. Some, we will see on the way.
__warning__
Color image loaded by OpenCV is in BGR mode. But Matplotlib displays in RGB mode. So color images
will not be displayed correctly in Matplotlib if image is read with OpenCV. Please see the exercises
for more details.
Additional Resources
--------------------
@@ -140,4 +151,3 @@ Exercises
-# There is some problem when you try to load color image in OpenCV and display it in Matplotlib.
Read [this discussion](http://stackoverflow.com/a/15074748/1134940) and understand it.