# Rectangular Region

GRE - powerprep The area of rectangular region ABCD.jpg The area of trapezoidal region EFGH A) Quantity A is greater. B) Quandetermined fromr. C) The two quantities. The following code would be helpful for cropping the images and get them in a white background. Import cv2 import numpy as np # load the image imagepath = 'input image path' image = cv2.imread(imagepath) # create a mask with white pixels mask = np.ones(image.shape, dtype=np.uint8) mask.fill(255) # points to be cropped roicorners = np.array((0, 300), (1880, 300), (1880, 400), (0, 400. In this rectangle perimeter and area worksheet, learners use the grid to draw four different rectangles for the problem about tiling a school's cafeteria floor. Students then find the perimeter and area for each rectangle and answer the.

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### 12.5 Rectangles Rectangle commands operate on rectangular areas of the text:all the characters between a certain pair of columns, in a certainrange of lines. Emacs has commands to kill rectangles, yank killedrectangles, clear them out, fill them with blanks or text, or deletethem. Rectangle commands are useful with text in multicolumn formats,and for changing text into or out of such formats. To specify a rectangle for a command to work on, set the mark at onecorner and point at the opposite corner. The rectangle thus specifiedis called the region-rectangle. If point and the mark are inthe same column, the region-rectangle is empty. If they are in thesame line, the region-rectangle is one line high.

The region-rectangle is controlled in much the same way as theregion is controlled. But remember that a given combination of pointand mark values can be interpreted either as a region or as arectangle, depending on the command that uses them.

A rectangular region can also be marked using the mouse: click and dragC-M-mouse-1 from one corner of the rectangle to the opposite.

C-x r k

Kill the text of the region-rectangle, saving its contents as thelast killed rectangle (`kill-rectangle`).

C-x r M-w

Save the text of the region-rectangle as the last killed rectangle(`copy-rectangle-as-kill`).

C-x r d

Delete the text of the region-rectangle (`delete-rectangle`).

C-x r y

Yank the last killed rectangle with its upper left corner at point(`yank-rectangle`).

C-x r o

Insert blank space to fill the space of the region-rectangle(`open-rectangle`). This pushes the previous contents of theregion-rectangle to the right.

C-x r N

Insert line numbers along the left edge of the region-rectangle(`rectangle-number-lines`). This pushes the previous contents ofthe region-rectangle to the right.

C-x r c

Clear the region-rectangle by replacing all of its contents with spaces(`clear-rectangle`). M-x delete-whitespace-rectangle

Delete whitespace in each of the lines on the specified rectangle,starting from the left edge column of the rectangle.

C-x r t stringRET

Replace rectangle contents with string on each line(`string-rectangle`).

M-x string-insert-rectangle RETstringRET

Insert string on each line of the rectangle.

C-x SPC

### Double Integrals Over Rectangular Regions

Toggle Rectangle Mark mode (`rectangle-mark-mode`).When this mode is active, the region-rectangle is highlighted and canbe shrunk/grown, and the standard kill and yank commands operate on it.

The rectangle operations fall into two classes: commands to erase orinsert rectangles, and commands to make blank rectangles.

There are two ways to erase the text in a rectangle: C-x r d(`delete-rectangle`) to delete the text outright, or C-x rk (`kill-rectangle`) to remove the text and save it as thelast killed rectangle. In both cases, erasing theregion-rectangle is like erasing the specified text on each line ofthe rectangle; if there is any following text on the line, it movesbackwards to fill the gap.

Killing a rectangle is not killing in the usual sense; therectangle is not stored in the kill ring, but in a special place thatonly records the most recent rectangle killed. This is becauseyanking a rectangle is so different from yanking linear text thatdifferent yank commands have to be used. Yank-popping is not definedfor rectangles.

C-x r M-w (`copy-rectangle-as-kill`) is the equivalent ofM-w for rectangles: it records the rectangle as the lastkilled rectangle, without deleting the text from the buffer.

To yank the last killed rectangle, type C-x r y(`yank-rectangle`). The rectangle’s first line is inserted atpoint, the rectangle’s second line is inserted at the same horizontalposition one line vertically below, and so on. The number of linesaffected is determined by the height of the saved rectangle.

For example, you can convert two single-column lists into adouble-column list by killing one of the single-column lists as arectangle, and then yanking it beside the other list.

### Rectangular Region Fractions

You can also copy rectangles into and out of registers with C-x rr r and C-x r i r. See Rectangle Registers.

### Six Congruent Rectangular Regions

There are two commands you can use for making blank rectangles:C-x r c (`clear-rectangle`) blanks out existing text in theregion-rectangle, and C-x r o (`open-rectangle`) inserts ablank rectangle. ### Rectangular Region Definition

M-x delete-whitespace-rectangle deletes horizontal whitespacestarting from a particular column. This applies to each of the linesin the rectangle, and the column is specified by the left edge of therectangle. The right edge of the rectangle does not make anydifference to this command.

### Double Integral Over Rectangular Region

The command C-x r N (`rectangle-number-lines`) insertsline numbers along the left edge of the region-rectangle. Normally,the numbering begins from 1 (for the first line of the rectangle).With a prefix argument, the command prompts for a number to beginfrom, and for a format string with which to print the numbers(see Formatting Strings in The Emacs Lisp ReferenceManual).

The command C-x r t (`string-rectangle`) replaces thecontents of a region-rectangle with a string on each line. Thestring’s width need not be the same as the width of the rectangle. Ifthe string’s width is less, the text after the rectangle shifts left;if the string is wider than the rectangle, the text after therectangle shifts right.

### Area Of A Rectangular Region

The command M-x string-insert-rectangle is similar to`string-rectangle`, but inserts the string on each line,shifting the original text to the right.

The command C-x SPC (`rectangle-mark-mode`) toggleswhether the region-rectangle or the standard region is highlighted(first activating the region if necessary). When this mode is enabled,commands that resize the region (C-f, C-n etc.) doso in a rectangular fashion, and killing and yanking operate on therectangle. See Killing. The mode persists only as long as theregion is active.

Unlike the standard region, the region-rectangle can have its cornersextended past the end of buffer, or inside stretches of white spacethat point normally cannot enter, like in the middle of a TABcharacter.

When the region is in rectangle-mark-mode, C-x C-x runs thecommand `rectangle-exchange-point-and-mark`, which cycles betweenthe four corners of the region-rectangle. This comes in handy if youwant to modify the dimensions of the region-rectangle before invokingan operation on the marked text.

### Rectangular Region

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