Typography

%% Text revolution

% This script generate surface of revolution from SVG path.

% Code will parse only absolute path in the file.Some minor tweaks

% will be required to get good results in some cases.

function revolText

fid = fopen('courier.txt','r'); %try some more files

M = [0 0]; %current point

L = [0 0]; %end point of line

x = zeros(1,3);

y = zeros(1,3);

% Origin in SVG coordinate system lies at top left corner.

% On the other hand origin in MATLAB lies at bottom left.

% This makes the SVG y-axis inverted in MATLAB.So we can subtract

% a large value from SVG y-coorinate to make it suitable for MATLAB

height = 150;

% These blank arrays will be filled while parsing the file.x and y

% coordinates of curve and lines will be kept in these arrays.When

% an new path is encountered all the elements in these arrays are

% removed.

xcord = [];

ycord = [];

% Counter to store total number of path in file.

countM = 0;

rough = ' '; %character to store space between points

cmap = hsv(128);

%% Parse file

while ~feof(fid)

dat=fscanf(fid,'%c',1);

switch dat

case 'M' %move to a new point

% A new path is starting at this point.save the previously

% stored point and start collecting new points.

m1 = fscanf(fid,'%g',1);

rough = fscanf(fid,'%c',1);

m2 = fscanf(fid,'%g',1);

M = [m1 m2];

% Rotate the path that was completed in previous steps

if ~isempty(xcord)

n = 10;

t = linspace(0,-pi/2,n);

theta = repmat(t,length(xcord),1);

% All the x coordinates will remain unchanged

% Duplicate x and y coordinates.Previously x and y were

% lying on the plane now z will be added to make 3d.

xpos = repmat(xcord,1,n);

ypos = repmat(ycord,1,n);

X = xpos;

%Size of z is same as x

Z = zeros(size(xpos));

%Rotate y and z coordinate by angle theta

[Z,Y] = transform2d(Z,ypos,0,0,theta,0,0);

%Convert to face and vertices

[faces,vertices,colmap]=surf2patch(X,Y,Z);

patch('faces',faces,'vertices',vertices,'facecolor',cmap(countM,:));

end

% ready to store new path

xcord = [];

ycord = [];

countM = countM+1;

xcord = [xcord;m1];

ycord = [ycord;height-m2];%make y upside down.

case 'C' %bezier curve

% Read 3 pair of numbers from file.

for k = 1:3

x(k) = fscanf(fid,'%g',1);

rough = fscanf(fid,'%c',1);

y(k) = fscanf(fid,'%g',1);

end

% calculate the bezier curve

[a,b]=bezierQuad([M(1) x],height-[M(2) y],20);%make y upside down.

% Last point in bezier curve is the new current point

M=[x(3) y(3)];

xcord=[xcord;a'];

ycord=[ycord;b'];

case 'L' %line

% Read two numbers from file.

l1 = fscanf(fid,'%g',1);

rough = fscanf(fid,'%c',1);

l2 = fscanf(fid,'%g',1);

L = [l1 l2];

xcord = [xcord;l1];

ycord = [ycord;height-l2]; %make y upside down.

% These two points will be the current point.

M = L;

otherwise

%do nothing

end

end

%% Draw the last path

% M moveto will not be the last.When file ends the last path

% has completed.

n = 10;

t = linspace(0,-pi/2,n);

theta = repmat(t,length(xcord),1);

xpos = repmat(xcord,1,n);

ypos = repmat(ycord,1,n);

X = xpos;

Z = zeros(size(xpos));

[Z,Y] = transform2d(Z,ypos,0,0,theta,0,0);

[faces,vertices,colmap] = surf2patch(X,Y,Z);

patch('faces',faces,'vertices',vertices,'facecolor',cmap(countM,:));

axis equal,view(3)

%Close the file

fclose(fid);

return %revolText end here

%% 2D Tranformation

% Function to perform transformation in 2d plane.

function [xd,yd]=transform2d(x,y,tx,ty,phi,xr,yr)

%tx,ty a scalar value .Point of translation

%phi a scalar value.Angle of rotation

%xr,yr a scalar value.radius of rotation

xd = x.*cos(phi)-y.*sin(phi)+xr.*(1-cos(phi))+yr.*sin(phi)+tx;

yd = x.*sin(phi)+y.*cos(phi)+yr.*(1-cos(phi))-xr.*sin(phi)+ty;

return

%% Bezier Curve

% Function claculates 2d bezier curve points

function [bx,by] = bezierQuad(x,y,n)

%Function to calculate bezier curve points using DeCasteljau Algorithm

%Taken from http://cubic.org/docs/bezier.htm

%n = no of points in bezier curve

%x = x coordinates of control point

%y = y coordinates of control point

t = linspace(0,1,n);

N = length(x);

qx = zeros(N,n);

qy = zeros(N,n);

bx = qx(1,:);

by = qy(1,:);

for k = 1:N-1

if k == 1

for i = 1:N-1

qx(i,:) = x(i)+(x(i+1)-x(i)).*t;

qy(i,:) = y(i)+(y(i+1)-y(i)).*t;

end

else

for i = 1:N-k+1

qx(i,:) = qx(i,:)+(qx(i+1,:)-qx(i,:)).*t;

qy(i,:) = qy(i,:)+(qy(i+1,:)-qy(i,:)).*t;

end

end

end

bx = qx(1,:);

by = qy(1,:);

return

%% Tangent to curve

function tangentToPath

% Code reads the path extracted from SVG file and draw

% tangent on each point.File used in this code contains path

% that is taken from a SVG file made in Inkscape.

%

% Line to be used as tangent.Coordinates are converted to

% polar.

xx = -5:5;

yy = zeros(1,length(xx));

[phi,r] = cart2pol(xx,yy);

% open the file

fid = fopen('typo.txt','r');

count = 0;

L = [0 0];

M = [0 0];

x = zeros(1,3);

y = zeros(1,3);

% Origin in SVG coordinates is located at top left corner of screen.

% Before drawing it has to be made upside down.

height = 750;

noOfBezierPoints = 10;

%% Start reading SVG path

while ~feof(fid)

dat = fscanf(fid,'%c',1);

switch dat

case 'M' % Move the current position

m1 = fscanf(fid,'%g',1);

c = fscanf(fid,'%c',1);

m2 = fscanf(fid,'%g',1);

M = [m1 m2];

count = count + 1;

case 'C' % Quadratic Bezier curve

%Read control points of curve

for k = 1:3

x(k) = fscanf(fid,'%g',1);

c = fscanf(fid,'%c',1);

y(k) = fscanf(fid,'%g',1);

end

%Calculate bezier curve points

[a,b] = bezier([M(1) x],height-[M(2) y],noOfBezierPoints);

%find and draw the tangent to each point on curve

for k = 2:length(a)

theta = atan2(b(k)-b(k-1),a(k)-a(k-1));

[xx,yy] = pol2cart(phi+theta,r);

line(xx+a(k),yy+b(k),'color',[0 0 0]);

end

%move the current position to the last control point of curve

M = [x(3) y(3)];

case 'L' %Straight line

%Read points of straight line

l1 = fscanf(fid,'%g',1);

c = fscanf(fid,'%c',1);

l2 = fscanf(fid,'%g',1);

L = [l1 l2];

line([M(1) L(1)],height-[M(2) L(2)],'color',[0 0 0]);

theta = atan2(M(2)-L(2),M(1)-L(1));

[xx,yy] = pol2cart(phi+theta,r);

line(xx+L(1),height-(yy+L(2)),'color',[0 0 0]);

%move the current point to new position

M = L;

otherwise

%do nothing

end

end

axis equal off

fclose(fid);

%% Bezier Curve

% Function claculates 2d bezier curve points

function [bx,by] = bezier(x,y,n)

%Function to calculate bezier curve points using DeCasteljau Algorithm

%Taken from http://cubic.org/docs/bezier.htm

%n = no of points in bezier curve

%x = x coordinates of control point

%y = y coordinates of control point

t = linspace(0,1,n);

N = length(x);

qx = zeros(N,n);

qy = zeros(N,n);

bx = qx(1,:);

by = qy(1,:);

for k = 1:N-1

if k == 1

for i = 1:N-1

qx(i,:) = x(i)+(x(i+1)-x(i)).*t;

qy(i,:) = y(i)+(y(i+1)-y(i)).*t;

end

else

for i = 1:N-k+1

qx(i,:) = qx(i,:)+(qx(i+1,:)-qx(i,:)).*t;

qy(i,:) = qy(i,:)+(qy(i+1,:)-qy(i,:)).*t;

end

end

end

bx = qx(1,:);

by = qy(1,:);

return