How to calculate width and height of text in jspdf

Question

I'm facing some issues while creating tables in jspdf. I could not find any good related docs, but if anyone knows one, please share.

I found two related methods:

1) doc.getStringUnitWidth(text, {widths:12,kerning:2});

2) doc.getTextDimensions(text)

What does widths and kerning mean in the first method? What should I provide? Which method should I use to get the width and height of text?

My goal is to solve some issues related to overlapping cell content, wrapping of text and text overflow relative to the page width.

Answer 1

You might want to look at the AutoTable plugin for generating tables with jsPDF. I found the built in plugin hard to work with and isn't documented at all.

The best way I have found to calculate the width is simply doing this:

var doc = new jsPDF();
var width = doc.getTextWidth('Text');
console.log(width);

If you really need to calculate the height getDimensions() might be an option. However, it is not pixel perfect and looking at the source I doubt it will work for anything but pt. Here is an example:

var doc = new jsPDF('p', 'pt');
var dim = doc.getTextDimensions('Text');
console.log(dim); // Object {w: 24.149968818897642, h: 19.499975433070865}

Answer 2

I found this question looking for answers to a similar issue. Unfortunately, the answers provided did not solve my problem, but I figure what I did find out may help other people stumbling onto this question.

As already mentioned, the .getStringUnitWidth(text) will return the width of a string (in pt). I could never find any explanation of the options like "kerning" or "widths" in the documentation or in the actual .js file. I also noticed with my own usage that this method was actually underestimating widths by ~10%, which started to add up very quickly. Finally, this did not account for fonts that were bold, italicized or bold and italicized.

Since I required a high level of accuracy, I ended up calculating the width of each character on my own and using this to calculate a string width (by totaling the width of each character in a string).

Below are the font widths at size 1 (in pt) for each character accepted by jsPDF in the 3 default fonts (helvetica, times, courier):

helvetica
char    unicode   normal   bold     italic   bolditalic
        32        0.278    0.278    0.278    0.278
!       33        0.278    0.333    0.278    0.333
"       34        0.355    0.474    0.355    0.474
#       35        0.556    0.556    0.556    0.556
$       36        0.556    0.556    0.556    0.556
%       37        0.889    0.889    0.889    0.889
&       38        0.667    0.722    0.667    0.722
'       39        0.191    0.238    0.191    0.238
(       40        0.333    0.333    0.333    0.333
)       41        0.333    0.333    0.333    0.333
*       42        0.389    0.389    0.389    0.389
+       43        0.584    0.584    0.584    0.584
,       44        0.278    0.278    0.278    0.278
-       45        0.333    0.333    0.333    0.333
.       46        0.278    0.278    0.278    0.278
/       47        0.278    0.278    0.278    0.278
0       48        0.556    0.556    0.556    0.556
1       49        0.556    0.556    0.556    0.556
2       50        0.556    0.556    0.556    0.556
3       51        0.556    0.556    0.556    0.556
4       52        0.556    0.556    0.556    0.556
5       53        0.556    0.556    0.556    0.556
6       54        0.556    0.556    0.556    0.556
7       55        0.556    0.556    0.556    0.556
8       56        0.556    0.556    0.556    0.556
9       57        0.556    0.556    0.556    0.556
:       58        0.278    0.333    0.278    0.333
;       59        0.278    0.333    0.278    0.333
<       60        0.584    0.584    0.584    0.584
=       61        0.584    0.584    0.584    0.584
>       62        0.584    0.584    0.584    0.584
?       63        0.556    0.611    0.556    0.611
@       64        1.015    0.975    1.015    0.975
A       65        0.667    0.722    0.667    0.722
B       66        0.667    0.722    0.667    0.722
C       67        0.722    0.722    0.722    0.722
D       68        0.722    0.722    0.722    0.722
E       69        0.667    0.667    0.667    0.667
F       70        0.611    0.611    0.611    0.611
G       71        0.778    0.778    0.778    0.778
H       72        0.722    0.722    0.722    0.722
I       73        0.278    0.278    0.278    0.278
J       74        0.500    0.556    0.500    0.556
K       75        0.667    0.722    0.667    0.722
L       76        0.556    0.611    0.556    0.611
M       77        0.833    0.833    0.833    0.833
N       78        0.722    0.722    0.722    0.722
O       79        0.778    0.778    0.778    0.778
P       80        0.667    0.667    0.667    0.667
Q       81        0.778    0.778    0.778    0.778
R       82        0.722    0.722    0.722    0.722
S       83        0.667    0.667    0.667    0.667
T       84        0.611    0.611    0.611    0.611
U       85        0.722    0.722    0.722    0.722
V       86        0.667    0.667    0.667    0.667
W       87        0.944    0.944    0.944    0.944
X       88        0.667    0.667    0.667    0.667
Y       89        0.667    0.667    0.667    0.667
Z       90        0.611    0.611    0.611    0.611
[       91        0.278    0.333    0.278    0.333
\       92        0.278    0.278    0.278    0.278
]       93        0.278    0.333    0.278    0.333
^       94        0.469    0.584    0.469    0.584
_       95        0.556    0.556    0.556    0.556
`       96        0.333    0.333    0.333    0.333
a       97        0.556    0.556    0.556    0.556
b       98        0.556    0.611    0.556    0.611
c       99        0.500    0.556    0.500    0.556
d       100       0.556    0.611    0.556    0.611                      
e       101       0.556    0.556    0.556    0.556                      
f       102       0.278    0.333    0.278    0.333                      
g       103       0.556    0.611    0.556    0.611                      
h       104       0.556    0.611    0.556    0.611                      
i       105       0.222    0.278    0.222    0.278                      
j       106       0.222    0.278    0.222    0.278                      
k       107       0.500    0.556    0.500    0.556                      
l       108       0.222    0.278    0.222    0.278                      
m       109       0.833    0.889    0.833    0.889                      
n       110       0.556    0.611    0.556    0.611                      
o       111       0.556    0.611    0.556    0.611                      
p       112       0.556    0.611    0.556    0.611                      
q       113       0.556    0.611    0.556    0.611                      
r       114       0.333    0.389    0.333    0.389                      
s       115       0.500    0.556    0.500    0.556                      
t       116       0.278    0.333    0.278    0.333                      
u       117       0.556    0.611    0.556    0.611                      
v       118       0.500    0.556    0.500    0.556                      
w       119       0.722    0.778    0.722    0.778                      
x       120       0.500    0.556    0.500    0.556                      
y       121       0.500    0.556    0.500    0.556                      
z       122       0.500    0.500    0.500    0.500                      
{       123       0.334    0.389    0.334    0.389                      
|       124       0.260    0.280    0.260    0.280                      
}       125       0.334    0.389    0.334    0.389                      
~       126       0.584    0.584    0.584    0.584                      
€       128       0.556    0.556    0.556    0.556                      
‚       130       0.222    0.278    0.222    0.278                      
ƒ       131       0.556    0.556    0.556    0.556                      
„       132       0.333    0.500    0.333    0.500                      
…       133       1.000    1.000    1.000    1.000                      
†       134       0.556    0.556    0.556    0.556                      
‡       135       0.556    0.556    0.556    0.556                      
ˆ       136       0.333    0.333    0.333    0.333                      
‰       137       1.000    1.000    1.000    1.000                      
Š       138       0.667    0.667    0.667    0.667                      
‹       139       0.333    0.333    0.333    0.333                      
Π      140       1.000    1.000    1.000    1.000                      
Ž       142       0.611    0.611    0.611    0.611                      
‘       145       0.222    0.278    0.222    0.278                      
’       146       0.222    0.278    0.222    0.278                      
“       147       0.333    0.500    0.333    0.500                      
”       148       0.333    0.500    0.333    0.500                      
•       149       0.350    0.350    0.350    0.350                      
–       150       0.556    0.556    0.556    0.556                      
—       151       1.000    1.000    1.000    1.000                      
˜       152       0.333    0.333    0.333    0.333                      
™       153       1.000    1.000    1.000    1.000                      
š       154       0.500    0.556    0.500    0.556                      
›       155       0.333    0.333    0.333    0.333                      
œ       156       0.944    0.944    0.944    0.944                      
ž       158       0.500    0.500    0.500    0.500                      
Ÿ       159       0.667    0.667    0.667    0.667                      
        160       0.278    0.278    0.278    0.278                      
¡       161       0.333    0.333    0.333    0.333                      
¢       162       0.556    0.556    0.556    0.556                      
£       163       0.556    0.556    0.556    0.556                      
¤       164       0.556    0.556    0.556    0.556                      
¥       165       0.556    0.556    0.556    0.556                      
¦       166       0.260    0.280    0.260    0.280                      
§       167       0.556    0.556    0.556    0.556                      
¨       168       0.333    0.333    0.333    0.333                      
©       169       0.737    0.737    0.737    0.737                      
ª       170       0.370    0.370    0.370    0.370                      
«       171       0.556    0.556    0.556    0.556                      
¬       172       0.584    0.584    0.584    0.584                      
-       173       0.333    0.333    0.333    0.333                      
®       174       0.737    0.737    0.737    0.737                      
¯       175       0.552    0.552    0.552    0.552                      
°       176       0.400    0.400    0.400    0.400                      
±       177       0.549    0.549    0.549    0.549                      
²       178       0.333    0.333    0.333    0.333                      
³       179       0.333    0.333    0.333    0.333                      
´       180       0.333    0.333    0.333    0.333                      
µ       181       0.576    0.576    0.576    0.576                      
¶       182       0.537    0.556    0.537    0.556                      
·       183       0.333    0.333    0.333    0.333                      
¸       184       0.333    0.333    0.333    0.333                      
¹       185       0.333    0.333    0.333    0.333                      
º       186       0.365    0.365    0.365    0.365                      
»       187       0.556    0.556    0.556    0.556                      
¼       188       0.834    0.834    0.834    0.834                      
½       189       0.834    0.834    0.834    0.834                      
¾       190       0.834    0.834    0.834    0.834                      
¿       191       0.611    0.611    0.611    0.611                      
À       192       0.667    0.722    0.667    0.722                      
Á       193       0.667    0.722    0.667    0.722                      
       194       0.667    0.722    0.667    0.722                      
à      195       0.667    0.722    0.667    0.722                      
Ä       196       0.667    0.722    0.667    0.722                      
Å       197       0.667    0.722    0.667    0.722                      
Æ       198       1.000    1.000    1.000    1.000                      
Ç       199       0.722    0.722    0.722    0.722                      
È       200       0.667    0.667    0.667    0.667                      
É       201       0.667    0.667    0.667    0.667                      
Ê       202       0.667    0.667    0.667    0.667                      
Ë       203       0.667    0.667    0.667    0.667                      
Ì       204       0.278    0.278    0.278    0.278                      
Í       205       0.278    0.278    0.278    0.278                      
Î       206       0.278    0.278    0.278    0.278                      
Ï       207       0.278    0.278    0.278    0.278                      
Ð       208       0.722    0.722    0.722    0.722                      
Ñ       209       0.722    0.722    0.722    0.722                      
Ò       210       0.778    0.778    0.778    0.778                      
Ó       211       0.778    0.778    0.778    0.778                      
Ô       212       0.778    0.778    0.778    0.778                      
Õ       213       0.778    0.778    0.778    0.778                      
Ö       214       0.778    0.778    0.778    0.778                      
×       215       0.584    0.584    0.584    0.584                      
Ø       216       0.778    0.778    0.778    0.778                      
Ù       217       0.722    0.722    0.722    0.722                      
Ú       218       0.722    0.722    0.722    0.722                      
Û       219       0.722    0.722    0.722    0.722                      
Ü       220       0.722    0.722    0.722    0.722                      
Ý       221       0.667    0.667    0.667    0.667                      
Þ       222       0.667    0.667    0.667    0.667                      
ß       223       0.611    0.611    0.611    0.611                      
à       224       0.556    0.556    0.556    0.556                      
á       225       0.556    0.556    0.556    0.556                      
â       226       0.556    0.556    0.556    0.556                      
ã       227       0.556    0.556    0.556    0.556                      
ä       228       0.556    0.556    0.556    0.556                      
å       229       0.556    0.556    0.556    0.556                      
æ       230       0.889    0.889    0.889    0.889                      
ç       231       0.500    0.556    0.500    0.556                      
è       232       0.556    0.556    0.556    0.556                      
é       233       0.556    0.556    0.556    0.556                      
ê       234       0.556    0.556    0.556    0.556                      
ë       235       0.556    0.556    0.556    0.556                      
ì       236       0.278    0.278    0.278    0.278                      
í       237       0.278    0.278    0.278    0.278                      
î       238       0.278    0.278    0.278    0.278                      
ï       239       0.278    0.278    0.278    0.278                      
ð       240       0.556    0.611    0.556    0.611                      
ñ       241       0.556    0.611    0.556    0.611                      
ò       242       0.556    0.611    0.556    0.611                      
ó       243       0.556    0.611    0.556    0.611                      
ô       244       0.556    0.611    0.556    0.611                      
õ       245       0.556    0.611    0.556    0.611                      
ö       246       0.556    0.611    0.556    0.611                      
÷       247       0.549    0.549    0.549    0.549                      
ø       248       0.611    0.611    0.611    0.611                      
ù       249       0.556    0.611    0.556    0.611                      
ú       250       0.556    0.611    0.556    0.611                      
û       251       0.556    0.611    0.556    0.611                      
ü       252       0.556    0.611    0.556    0.611                      
ý       253       0.500    0.556    0.500    0.556                      
þ       254       0.556    0.611    0.556    0.611                      
ÿ       255       0.500    0.556    0.500    0.556                      

times
char    unicode   normal   bold     italic   bolditalic
        32        0.250    0.250    0.250    0.250                      
!       33        0.333    0.333    0.333    0.389                      
"       34        0.408    0.555    0.420    0.555                      
#       35        0.500    0.500    0.500    0.500                      
$       36        0.500    0.500    0.500    0.500                      
%       37        0.833    1.000    0.833    0.833                      
&       38        0.778    0.833    0.778    0.778                      
'       39        0.180    0.278    0.214    0.278                      
(       40        0.333    0.333    0.333    0.333                      
)       41        0.333    0.333    0.333    0.333                      
*       42        0.500    0.500    0.500    0.500                      
+       43        0.564    0.570    0.675    0.570                      
,       44        0.250    0.250    0.250    0.250                      
-       45        0.333    0.333    0.333    0.333                      
.       46        0.250    0.250    0.250    0.250                      
/       47        0.278    0.278    0.278    0.278                      
0       48        0.500    0.500    0.500    0.500                      
1       49        0.500    0.500    0.500    0.500                      
2       50        0.500    0.500    0.500    0.500                      
3       51        0.500    0.500    0.500    0.500                      
4       52        0.500    0.500    0.500    0.500                      
5       53        0.500    0.500    0.500    0.500                      
6       54        0.500    0.500    0.500    0.500                      
7       55        0.500    0.500    0.500    0.500                      
8       56        0.500    0.500    0.500    0.500                      
9       57        0.500    0.500    0.500    0.500                      
:       58        0.278    0.333    0.333    0.333                      
;       59        0.278    0.333    0.333    0.333                      
<       60        0.564    0.570    0.675    0.570                      
=       61        0.564    0.570    0.675    0.570                      
>       62        0.564    0.570    0.675    0.570                      
?       63        0.444    0.500    0.500    0.500                      
@       64        0.921    0.930    0.920    0.832                      
A       65        0.722    0.722    0.611    0.667                      
B       66        0.667    0.667    0.611    0.667                      
C       67        0.667    0.722    0.667    0.667                      
D       68        0.722    0.722    0.722    0.722                      
E       69        0.611    0.667    0.611    0.667                      
F       70        0.556    0.611    0.611    0.667                      
G       71        0.722    0.778    0.722    0.722                      
H       72        0.722    0.778    0.722    0.778                      
I       73        0.333    0.389    0.333    0.389                      
J       74        0.389    0.500    0.444    0.500                      
K       75        0.722    0.778    0.667    0.667                      
L       76        0.611    0.667    0.556    0.611                      
M       77        0.889    0.944    0.833    0.889                      
N       78        0.722    0.722    0.667    0.722                      
O       79        0.722    0.778    0.722    0.722                      
P       80        0.556    0.611    0.611    0.611                      
Q       81        0.722    0.778    0.722    0.722                      
R       82        0.667    0.722    0.611    0.667                      
S       83        0.556    0.556    0.500    0.556                      
T       84        0.611    0.667    0.556    0.611                      
U       85        0.722    0.722    0.722    0.722                      
V       86        0.722    0.722    0.611    0.667                      
W       87        0.944    1.000    0.833    0.889                      
X       88        0.722    0.722    0.611    0.667                      
Y       89        0.722    0.722    0.556    0.611                      
Z       90        0.611    0.667    0.556    0.611                      
[       91        0.333    0.333    0.389    0.333                      
\       92        0.278    0.278    0.278    0.278                      
]       93        0.333    0.333    0.389    0.333                      
^       94        0.469    0.581    0.422    0.570                      
_       95        0.500    0.500    0.500    0.500                      
`       96        0.333    0.333    0.333    0.333                      
a       97        0.444    0.500    0.500    0.500                      
b       98        0.500    0.556    0.500    0.500                      
c       99        0.444    0.444    0.444    0.444                      
d       100       0.500    0.556    0.500    0.500                      
e       101       0.444    0.444    0.444    0.444                      
f       102       0.333    0.333    0.278    0.333                      
g       103       0.500    0.500    0.500    0.500                      
h       104       0.500    0.556    0.500    0.556                      
i       105       0.278    0.278    0.278    0.278                      
j       106       0.278    0.333    0.278    0.278                      
k       107       0.500    0.556    0.444    0.500                      
l       108       0.278    0.278    0.278    0.278                      
m       109       0.778    0.833    0.722    0.778                      
n       110       0.500    0.556    0.500    0.556                      
o       111       0.500    0.500    0.500    0.500                      
p       112       0.500    0.556    0.500    0.500                      
q       113       0.500    0.556    0.500    0.500                      
r       114       0.333    0.444    0.389    0.389                      
s       115       0.389    0.389    0.389    0.389                      
t       116       0.278    0.333    0.278    0.278                      
u       117       0.500    0.556    0.500    0.556                      
v       118       0.500    0.500    0.444    0.444                      
w       119       0.722    0.722    0.667    0.667                      
x       120       0.500    0.500    0.444    0.500                      
y       121       0.500    0.500    0.444    0.444                      
z       122       0.444    0.444    0.389    0.389                      
{       123       0.480    0.394    0.400    0.348                      
|       124       0.200    0.220    0.275    0.220                      
}       125       0.480    0.394    0.400    0.348                      
~       126       0.541    0.520    0.541    0.570                      
€       128       0.500    0.500    0.500    0.500                      
‚       130       0.333    0.333    0.333    0.333                      
ƒ       131       0.500    0.500    0.500    0.500                      
„       132       0.444    0.500    0.556    0.500                      
…       133       1.000    1.000    0.889    1.000                      
†       134       0.500    0.500    0.500    0.500                      
‡       135       0.500    0.500    0.500    0.500                      
ˆ       136       0.333    0.333    0.333    0.333                      
‰       137       1.000    1.000    1.000    1.000                      
Š       138       0.556    0.556    0.500    0.556                      
‹       139       0.333    0.333    0.333    0.333                      
Π      140       0.889    1.000    0.944    0.944                      
Ž       142       0.611    0.667    0.556    0.611                      
‘       145       0.333    0.333    0.333    0.333                      
’       146       0.333    0.333    0.333    0.333                      
“       147       0.444    0.500    0.556    0.500                      
”       148       0.444    0.500    0.556    0.500                      
•       149       0.350    0.350    0.350    0.350                      
–       150       0.500    0.500    0.500    0.500                      
—       151       1.000    1.000    0.889    1.000                      
˜       152       0.333    0.333    0.333    0.333                      
™       153       0.980    1.000    0.980    1.000                      
š       154       0.389    0.389    0.389    0.389                      
›       155       0.333    0.333    0.333    0.333                      
œ       156       0.722    0.722    0.667    0.722                      
ž       158       0.444    0.444    0.389    0.389                      
Ÿ       159       0.722    0.722    0.556    0.611                      
        160       0.250    0.250    0.250    0.250                      
¡       161       0.333    0.333    0.389    0.389                      
¢       162       0.500    0.500    0.500    0.500                      
£       163       0.500    0.500    0.500    0.500                      
¤       164       0.500    0.500    0.500    0.500                      
¥       165       0.500    0.500    0.500    0.500                      
¦       166       0.200    0.220    0.275    0.220                      
§       167       0.500    0.500    0.500    0.500                      
¨       168       0.333    0.333    0.333    0.333                      
©       169       0.760    0.747    0.760    0.747                      
ª       170       0.276    0.300    0.276    0.266                      
«       171       0.500    0.500    0.500    0.500                      
¬       172       0.564    0.570    0.675    0.606                      
-       173       0.333    0.333    0.333    0.333                      
®       174       0.760    0.747    0.760    0.747                      
¯       175       0.500    0.500    0.500    0.500                      
°       176       0.400    0.400    0.400    0.400                      
±       177       0.549    0.549    0.549    0.549                      
²       178       0.300    0.300    0.300    0.300                      
³       179       0.300    0.300    0.300    0.300                      
´       180       0.333    0.333    0.333    0.333                      
µ       181       0.576    0.576    0.576    0.576                      
¶       182       0.453    0.540    0.523    0.500                      
·       183       0.333    0.333    0.250    0.250                      
¸       184       0.333    0.333    0.333    0.333                      
¹       185       0.300    0.300    0.300    0.300                      
º       186       0.310    0.330    0.310    0.300                      
»       187       0.500    0.500    0.500    0.500                      
¼       188       0.750    0.750    0.750    0.750                      
½       189       0.750    0.750    0.750    0.750                      
¾       190       0.750    0.750    0.750    0.750                      
¿       191       0.444    0.500    0.500    0.500                      
À       192       0.722    0.722    0.611    0.667                      
Á       193       0.722    0.722    0.611    0.667                      
       194       0.722    0.722    0.611    0.667                      
à      195       0.722    0.722    0.611    0.667                      
Ä       196       0.722    0.722    0.611    0.667                      
Å       197       0.722    0.722    0.611    0.667                      
Æ       198       0.889    1.000    0.889    0.944                      
Ç       199       0.667    0.722    0.667    0.667                      
È       200       0.611    0.667    0.611    0.667                      
É       201       0.611    0.667    0.611    0.667                      
Ê       202       0.611    0.667    0.611    0.667                      
Ë       203       0.611    0.667    0.611    0.667                      
Ì       204       0.333    0.389    0.333    0.389                      
Í       205       0.333    0.389    0.333    0.389                      
Î       206       0.333    0.389    0.333    0.389                      
Ï       207       0.333    0.389    0.333    0.389                      
Ð       208       0.722    0.722    0.722    0.722                      
Ñ       209       0.722    0.722    0.667    0.722                      
Ò       210       0.722    0.778    0.722    0.722                      
Ó       211       0.722    0.778    0.722    0.722                      
Ô       212       0.722    0.778    0.722    0.722                      
Õ       213       0.722    0.778    0.722    0.722                      
Ö       214       0.722    0.778    0.722    0.722                      
×       215       0.564    0.570    0.675    0.570                      
Ø       216       0.722    0.778    0.722    0.722                      
Ù       217       0.722    0.722    0.722    0.722                      
Ú       218       0.722    0.722    0.722    0.722                      
Û       219       0.722    0.722    0.722    0.722                      
Ü       220       0.722    0.722    0.722    0.722                      
Ý       221       0.722    0.722    0.556    0.611                      
Þ       222       0.556    0.611    0.611    0.611                      
ß       223       0.500    0.556    0.500    0.500                      
à       224       0.444    0.500    0.500    0.500                      
á       225       0.444    0.500    0.500    0.500                      
â       226       0.444    0.500    0.500    0.500                      
ã       227       0.444    0.500    0.500    0.500                      
ä       228       0.444    0.500    0.500    0.500                      
å       229       0.444    0.500    0.500    0.500                      
æ       230       0.667    0.722    0.667    0.722                      
ç       231       0.444    0.444    0.444    0.444                      
è       232       0.444    0.444    0.444    0.444                      
é       233       0.444    0.444    0.444    0.444                      
ê       234       0.444    0.444    0.444    0.444                      
ë       235       0.444    0.444    0.444    0.444                      
ì       236       0.278    0.278    0.278    0.278                      
í       237       0.278    0.278    0.278    0.278                      
î       238       0.278    0.278    0.278    0.278                      
ï       239       0.278    0.278    0.278    0.278                      
ð       240       0.500    0.500    0.500    0.500                      
ñ       241       0.500    0.556    0.500    0.556                      
ò       242       0.500    0.500    0.500    0.500                      
ó       243       0.500    0.500    0.500    0.500                      
ô       244       0.500    0.500    0.500    0.500                      
õ       245       0.500    0.500    0.500    0.500                      
ö       246       0.500    0.500    0.500    0.500                      
÷       247       0.549    0.549    0.549    0.549                      
ø       248       0.500    0.500    0.500    0.500                      
ù       249       0.500    0.556    0.500    0.556                      
ú       250       0.500    0.556    0.500    0.556                      
û       251       0.500    0.556    0.500    0.556                      
ü       252       0.500    0.556    0.500    0.556                      
ý       253       0.500    0.500    0.444    0.444                      
þ       254       0.500    0.556    0.500    0.500                      
ÿ       255       0.500    0.500    0.444    0.444                      

courier
All characters in every style are 0.600 (font is monospaced)

Once you have determined the width of your string with the above table you need to convert the answer to your desired unit of measurement.

width (in inches) = (character or string width * font size) / (72 pt/in)
width (in mm) = (character or string width * font size * 25.4 mm/in) / (72 pt/in)

The only caveat to using the above I could think of was if your output pdf was making use of kerning pairs. My output files did not appear to be using kerning pairs, so I did not explore the issue further. If for some reason this is an issue for you, you would need to adjust your widths slightly for each kerning pair as it occurred.

The calculation of height is much less involved. The height of a single line of text is simply the font size. A line of text at size 10 will take up 10 pt.

If you are wanting to calculate multiple lines of text you will need to account for the "line height" (essentially the amount of whitespace between lines). In my testing I found that jsPDF uses a default line height of 115% (1.15x) of the font size. Thus your calculation of line height would become:

height = font size * number of lines * line height

Example:
height = 10 pt * 5 lines * 1.15
height = 57.5 pt

You then simply convert to your desired unit of measurement as above.

Answer 3

It's now included in jsPDF:

doc.getTextWidth(text);