Fetch rectangle (line segments)co ordinates from pdf using itextpdf - pdf

I want to get the line segments co ordinates total & line segments should come. I want to read the pdf table co ordinates so that I can fetch the text inside the co ordinates? I am getting only 6 line segments. What about the 7 line segment?
I am using this program to read the line segments from tables(rectangle)
iText : image on PDF only if the position is blank
output is :
50 50 150 50
150 50 150 150
150 150 50 150
150 50 200 50
200 50 200 150
200 150 150 150

The cause of this problem is that iText reports a rectangle drawing instruction as subpath containing three explicit lines (bottom, right, top) and sets its Closed property implying the fourth line (left):
public void rectangle(float x, float y, float w, float h) {
moveTo(x, y);
lineTo(x + w, y);
lineTo(x + w, y + h);
lineTo(x, y + h);
closeSubpath();
}
(com.itextpdf.kernel.geom.Path.rectangle(float, float, float, float))
The FreeSpaceFinder in the referenced answer, though, only considers the explicit subpath segments, not the implied one. Thus, for your two rectangles you only get 6 lines instead of the expected 8 lines.
To also get implied closing lines for each Subpath subpath, you have to check whether subpath.isClosed(), and if it is, you have to determine the end point of the last IShape segment in subpath.getSegments() and the start point of the first IShape segment and add a line connecting those points.

Related

The King's March

You’re given a chess board with dimension n x n. There’s a king at the bottom right square of the board marked with s. The king needs to reach the top left square marked with e. The rest of the squares are labeled either with an integer p (marking a point) or with x marking an obstacle. Note that the king can move up, left and up-left (diagonal) only. Find the maximum points the king can collect and the number of such paths the king can take in order to do so.
Input Format
The first line of input consists of an integer t. This is the number of test cases. Each test case contains a number n which denotes the size of board. This is followed by n lines each containing n space separated tokens.
Output Format
For each case, print in a separate line the maximum points that can be collected and the number of paths available in order to ensure maximum, both values separated by a space. If e is unreachable from s, print 0 0.
Sample Input
3
3
e 2 3
2 x 2
1 2 s
3
e 1 2
1 x 1
2 1 s
3
e 1 1
x x x
1 1 s
Sample Output
7 1
4 2
0 0
Constraints
1 <= t <= 100
2 <= n <= 200
1 <= p <= 9
I think this problem could be solved using dynamic-programing. We could use dp[i,j] to calculate the best number of points you can obtain by going from the right bottom corner to the i,j position. We can calculate dp[i,j], for a valid i,j, based on dp[i+1,j], dp[i,j+1] and dp[i+1,j+1] if this are valid positions(not out of the matrix or marked as x) and adding them the points obtained in the i,j cell. You should start computing from the bottom right corner to the left top, row by row and beginning from the last column.
For the number of ways you can add a new matrix ways and use it to store the number of ways.
This is an example code to show the idea:
dp[i,j] = dp[i+1,j+1] + board[i,j]
ways[i,j] = ways[i+1,j+1]
if dp[i,j] < dp[i+1,j] + board[i,j]:
dp[i,j] = dp[i+1,j] + board[i,j]
ways[i,j] = ways[i+1,j]
elif dp[i,j] == dp[i+1,j] + board[i,j]:
ways[i,j] += ways[i+1,j]
# check for i,j+1
This assuming all positions are valid.
The final result is stored in dp[0,0] and ways[0,0].
Brief Overview:
This problem can be solved through recursive method call, starting from nn till it reaches 00 which is the king's destination.
For the detailed explanation and the solution for this problem,check it out here -> https://www.callstacker.com/detail/algorithm-1

Complex Formulas within Excel Using VBA

I am working on vba code where I have data (for Slope Inclinometers) at various depths like so:
Depth A0 A180 Checksum B0 B180 Checksum
4.5 (-1256) 1258 2 (-394) 378 (-16)
4.5 (-1250) 1257 7 (-396) 376 (-20)
4.5 (-1257) 1257 0 (-400) 374 (-26)
Depth A0 A180 Checksum B0 B180 Checksum
5 (-1214) 1214 0 (-472) 459 (-13)
5 (-1215) 1212 -3 (-472) 455 (-17)
5 (-1216) 1211 -5 (-473) 455 (-18)
UNKNOWN AMOUNT OF DATA WILL BE PRESENT (depends how much the user transfers to this sheet)
Now I need to be able to calculate the A Axis Displacement, the B Axis Displacement, and the resultant which have formulas as followed:
A Axis Displacement = [((A0-A180)/2)-((A0*-A180*)/2))]*(constant/constant)
Where * is the initial readings which is always the first row of data at that specified depth.
B Axis Displacement = [((A0-A180)/2)-((A0*-A180*)/2))]*(constant/constant)
Where * is the initial readings which is always the first row of data at that specified depth.
Resultant = SQRT[(A Axis Displacement)^2 + (B Axis Displacement)^2]
I'm struggling to find examples of how I can implement this using vba as there will be various depths present (unknown amount) on the same sheet where the formula will need to start over at each new depth present.
Any helps/tips would be greatly appreciated!
how I can implement this using vba as there will be various depths present...
You still can do it purely with formulas and easy auto-fill, because the formula can find the the first occurrence of the current depth and perform all the necessary calculations, leaving blank at header rows or blank rows. For instance, you can enter these formulas at row 2 and fill down all the rows.
H2 (A Axis Displacement):
=IF(ISNUMBER($A2),0.5*(B2-C2-VLOOKUP($A2,$A:$F,2,0)+VLOOKUP($A2,$A:$F,3,0)), "")
I2 (B Axis Displacement):
=IF(ISNUMBER($A2),0.5*(E2-F2-VLOOKUP($A2,$A:$F,5,0)+VLOOKUP($A2,$A:$F,6,0)), "")
J2 (Resultant):
=IF(ISNUMBER($A2),SQRT(SUMSQ(H2,I2)),"")
p.s. in the displacements formulas I omitted the (constant/constant) factor as it is irrelevant to the answer, you can easily multiply the 0.5 factor by anything you need.

Core Animation - How to calculate duration so that two lines of different length are drawn at the same rate

I have two lines at different lengths
Line1 -----
Line2 -------------
How can I calculate the animation duration for each line so that they both are drawn at the same speed.
At the moment, I have a set value for duration
line1.duration = 1;
line2.duration = 1;
Because of the different lengths, line1's animation is slower than line2.
How can I calculate the animation duration with a fixed speed?
EDIT
Forgot to mention that line1 doesn't know line2's length as the lines are drawn in a loop. What i'm after is a constant velocity calculation / pixels per seconds
Try this:
line2.duration = lengthOfLine2 / lengthOfLine1 * line1.duration;
(substitute the appropriate values.)
I am assuming: Drawing at same rate - You mean both of them should end drawing simultaneously.
Suppose Line 1 : Length - 100 px
Suppose Line 2 : Length - 350 px
Then suppose 1 px takes 1 ms then Line 1 will take 100 ms
For Line 2 to take 100 ms it needs to draw (350/100 = 3.5 px/ms)
So suppose Short line takes time "t" for line of length "l1"
Then greater line should take time "l2/t" for line of length "l2"
for both of them to stop drawing simultaneously.

Hash function to iterate through a matrix

Given a NxN matrix and a (row,column) position, what is a method to select a different position in a random (or pseudo-random) order, trying to avoid collisions as much as possible?
For example: consider a 5x5 matrix and start from (1,2)
0 0 0 0 0
0 0 X 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
I'm looking for a method like
(x,y) hash (x,y);
to jump to a different position in the matrix, avoiding collisions as much as possible
(do not care how to return two different values, it doesn't matter, just think of an array).
Of course, I can simply use
row = rand()%N;
column = rand()%N;
but it's not that good to avoid collisions.
I thought I could apply twice a simple hash method for both row and column and use the results as new coordinates, but I'm not sure this is a good solution.
Any ideas?
Can you determine the order of the walk before you start iterating? If your matrices are large, this approach isn't space-efficient, but it is straightforward and collision-free. I would do something like:
Generate an array of all of the coordinates. Remove the starting position from the list.
Shuffle the list (there's sample code for a Fisher-Yates shuffle here)
Use the shuffled list for your walk order.
Edit 2 & 3: A modular approach: Given s array elements, choose a prime p of form 2+3*n, p>s. For i=1 to p, use cells (iii)%p when that value is in range 1...s-1. (For row-length r, cell #c subscripts are c%r, c/r.)
Effectively, this method uses H(i) = (iii) mod p as a hash function. The reference shows that as i ranges from 1 to p, H(i) takes on each of the values from 0 to p-1, exactly one time each.
For example, with s=25 and p=29 or 47, this uses cells in following order:
p=29: 1 8 6 9 13 24 19 4 14 17 22 18 11 7 12 3 15 10 5 16 20 23 2 21 0
p=47: 1 8 17 14 24 13 15 18 7 4 10 2 6 21 3 22 9 12 11 23 5 19 16 20 0
according to bc code like
s=25;p=29;for(i=1;i<=p;++i){t=(i^3)%p; if(t<s){print " ",t}}
The text above shows the suggestion I made in Edit 2 of my answer. The text below shows my first answer.
Edit 0: (This is the suggestion to which Seamus's comment applied): A simple method to go through a vector in a "random appearing" way is to repeatedly add d (d>1) to an index. This will access all elements if d and s are coprime (where s=vector length). Note, my example below is in terms of a vector; you could do the same thing independently on the other axis of your matrix, with a different delta for it, except a problem mentioned below would occur. Note, "coprime" means that gcd(d,s)=1. If s is variable, you'd need gcd() code.
Example: Say s is 10. gcd(s,x) is 1 for x in {1,3,7,9} and is not 1 for x in {2,4,5,6,8,10}. Suppose we choose d=7, and start with i=0. i will take on values 0, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, which modulo 10 is 0, 7, 4, 1, 8, 5, 2, 9, 6, 3, 0.
Edit 1 & 3: Unfortunately this will have a problem in the two-axis case; for example, if you use d=7 for x axis, and e=3 for y-axis, while the first 21 hits will be distinct, it will then continue repeating the same 21 hits. To address this, treat the whole matrix as a vector, use d with gcd(d,s)=1, and convert cell numbers to subscripts as above.
If you just want to iterate through the matrix, what is wrong with row++; if (row == N) {row = 0; column++}?
If you iterate through the row and the column independently, and each cycles back to the beginning after N steps, then the (row, column) pair will interate through only N of the N^2 cells of the matrix.
If you want to iterate through all of the cells of the matrix in pseudo-random order, you could look at questions here on random permutations.
This is a companion answer to address a question about my previous answer: How to find an appropriate prime p >= s (where s = the number of matrix elements) to use in the hash function H(i) = (i*i*i) mod p.
We need to find a prime of form 3n+2, where n is any odd integer such that 3*n+2 >= s. Note that n odd gives 3n+2 = 3(2k+1)+2 = 6k+5 where k need not be odd. In the example code below, p = 5+6*(s/6); initializes p to be a number of form 6k+5, and p += 6; maintains p in this form.
The code below shows that half-a-dozen lines of code are enough for the calculation. Timings are shown after the code, which is reasonably fast: 12 us at s=half a million, 200 us at s=half a billion, where us denotes microseconds.
// timing how long to find primes of form 2+3*n by division
// jiw 20 Sep 2011
#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
double ttime(double base) {
struct timeval tod;
gettimeofday(&tod, NULL);
return tod.tv_sec + tod.tv_usec/1e6 - base;
}
int main(int argc, char *argv[]) {
int d, s, p, par=0;
double t0=ttime(0);
++par; s=5000; if (argc > par) s = atoi(argv[par]);
p = 5+6*(s/6);
while (1) {
for (d=3; d*d<p; d+=2)
if (p%d==0) break;
if (d*d >= p) break;
p += 6;
}
printf ("p = %d after %.6f seconds\n", p, ttime(t0));
return 0;
}
Timing results on 2.5GHz Athlon 5200+:
qili ~/px > for i in 0 00 000 0000 00000 000000; do ./divide-timing 500$i; done
p = 5003 after 0.000008 seconds
p = 50021 after 0.000010 seconds
p = 500009 after 0.000012 seconds
p = 5000081 after 0.000031 seconds
p = 50000021 after 0.000072 seconds
p = 500000003 after 0.000200 seconds
qili ~/px > factor 5003 50021 500009 5000081 50000021 500000003
5003: 5003
50021: 50021
500009: 500009
5000081: 5000081
50000021: 50000021
500000003: 500000003
Update 1 Of course, timing is not determinate (ie, can vary substantially depending on the value of s, other processes on machine, etc); for example:
qili ~/px > time for i in 000 004 010 058 070 094 100 118 184; do ./divide-timing 500000$i; done
p = 500000003 after 0.000201 seconds
p = 500000009 after 0.000201 seconds
p = 500000057 after 0.000235 seconds
p = 500000069 after 0.000394 seconds
p = 500000093 after 0.000200 seconds
p = 500000099 after 0.000201 seconds
p = 500000117 after 0.000201 seconds
p = 500000183 after 0.000211 seconds
p = 500000201 after 0.000223 seconds
real 0m0.011s
user 0m0.002s
sys 0m0.004s
Consider using a double hash function to get a better distribution inside the matrix,
but given that you cannot avoid colisions, what I suggest is to use an array of sentinels
and mark the positions you visit, this way you are sure you get to visit a cell once.

How to Resize using Lanczos

I can easily calculate the values for sinc(x) curve used in Lanczos, and I have read the previous explanations about Lanczos resize, but being new to this area I do not understand how to actually apply them.
To resample with lanczos imagine you
overlay the output and input over
eachother, with points signifying
where the pixel locations are. For
each output pixel location you take a
box +- 3 output pixels from that
point. For every input pixel that lies
in that box, calculate the value of
the lanczos function at that location
with the distance from the output
location in output pixel coordinates
as the parameter. You then need to
normalize the calculated values by
scaling them so that they add up to 1.
After that multiply each input pixel
value with the corresponding scaling
value and add the results together to
get the value of the output pixel.
For example, what does "overlay the input and output" actually mean in programming terms?
In the equation given
lanczos(x) = {
0 if abs(x) > 3,
1 if x == 0,
else sin(x*pi)/x
}
what is x?
As a simple example, suppose I have an input image with 14 values (i.e. in addresses In0-In13):
20 25 30 35 40 45 50 45 40 35 30 25 20 15
and I want to scale this up by 2, i.e. to an image with 28 values (i.e. in addresses Out0-Out27).
Clearly, the value in address Out13 is going to be similar to the value in address In7, but which values do I actually multiply to calculate the correct value for Out13?
What is x in the algorithm?
If the values in your input data is at t coordinates [0 1 2 3 ...], then your output (which is scaled up by 2) has t coordinates at [0 .5 1 1.5 2 2.5 3 ...]. So to get the first output value, you center your filter at 0 and multiply by all of the input values. Then to get the second output, you center your filter at 1/2 and multiply by all of the input values. Etc ...