decksh is a domain-specific language (DSL) for generating deck markup.
decksh elements
go get github.com/ajstarks/decksh # install the package
go install github.com/ajstarks/decksh/cmd/decksh@latest # install the decksh command
deckshoverviewdeckshobject reference- Installing and Running decksh/pdfdeck
- Repository of decksh projects and visualizations
The Process function reads decksh commands from an io.Reader and writes deck markup to an io.Writer, returning an error.
For example:
package main
import (
"fmt"
"os"
"strings"
"github.com/ajstarks/decksh"
)
func main() {
input := `
deck
slide
ctext "hello, world" 50 50 10
eslide
edeck
`
err := decksh.Process(os.Stdout, strings.NewReader(input))
if err != nil {
fmt.Fprintf(os.Stderr, "%v\n", err)
}
}
Produces:
<deck>
<slide>
<text align="c" xp="50" yp="50" sp="10" >hello, world</text>
</slide>
</deck>
This repository also contains cmd/decksh, a client decksh command:
decksh reads from the specified input, and writes deck markup to the specified output destination:
$ decksh # input from stdin, output to stdout
$ decksh -o foo.xml # input from stdin, output to foo.xml
$ decksh foo.sh # input from foo.sh output to stdout
$ decksh -o foo.xml foo.sh # input from foo.sh output to foo.xml
Typically, decksh acts as the head of a rendering pipeline, where another deck client renders the markup.
This example uses pdfdeck
$ decksh text.dsh | pdfdeck -stdout -pagesize 1200,900 - > text.pdf
decksh hello, world:
// hello world
deck
slide "black" "white"
ctext "hello world" 50 25 15
circle 0 0 120 "blue"
eslide
edeck
produces:
This deck script:
// Example deck
midx=50
midy=50
iw=640
ih=480
imfile="follow.jpg"
imlink="https://budnitzbicycles.com"
imscale=58
dtop=87
opts="-fulldeck=f -textsize 1 -xlabel=2 -barwidth 1.5"
deck
slide "white" "black"
ctext "Deck elements" midx dtop 5
cimage "follow.jpg" "Dreams" 72 midy iw ih imscale imlink
textblock "Budnitz #1, Plainfield, NJ, May 10, 2015" 55 35 10 1 "serif" "white"
// List
blist 10 75 3
li "text, image, list"
li "rect, ellipse, polygon"
li "line, arc, curve"
elist
// Graphics
gy=10
c1="red"
c2="blue"
c3="green"
rect 15 gy 8 6 c1
ellipse 27.5 gy 8 6 c2
polygon "37 37 45" "7 13 10" c3
line 50 gy 60 gy 0.25 c1
arc 70 gy 10 8 0 180 0.25 c2
curve 80 gy 95 25 90 gy 0.25 c3
// Chart
chleft=10
chright=45
chtop=42
chtbottom=28
dchart -left chleft -right chright -top chtop -bottom chbottom opts AAPL.d
eslide
edeck
Produces:
Text, font, color, caption and link arguments follow Go conventions (surrounded by double quotes).
decksh (like the deck markup it produces) uses a traditional Cartesian coordinate system:
The origin (0,0) is at the lower left, x increases to the right, and y increases upwards. The coordinate system is
expliticly based on the percentages, with x and y ranging from 0-100. For example (50, 50) is the middle of the canvas, (100,100) is the upper right, (100,0) is the lower right, and (0,100) is the upper left.
Colors formats are:
- RGB: "rgb(n,n,n)", where n ranges from 0-255, for example "
"rgb(128,0,128)". - hex: "#rrggbb", for example
"#aa00aa", - HSV: hsv(hue,saturation,value), hue ranges from 0-360, saturation and value range from 0-100, for example
"hsv(360,30,30)"(pdfdeck and pngdeck support this syntax) - SVG color names.
Color gradients (used for slide backgrounds and rectangle and square fills) are specified as color1/color2/percent, for example, "blue/white/90"
Coordinates, dimensions, scales and opacities are floating point numbers ranging from from 0-100 (representing percentages of the canvas width and percent opacity).
Some arguments are optional, and if omitted defaults are applied (black for text, gray for graphics, 100% opacity).
Canvas size and image dimensions are in pixels.
Fonts may be:
- "sans"
- "serif"
- "mono"
- symbol"
deck
edeck
slide [bgcolor] [fgcolor]
eslide
Note that doc/edoc and page/epage are may also be used as synomyms for deck/edeck and slide/eslide.
canvas w h
id=<number> defines a constant, which may be then subtitited. For example:
x=10
y=20
text "hello, world" x y 5
The special identifier, deckshVersion contains the string denoting the version of decksh.
id+=<number> increment the value of id by <number>
x+=5
id-=<number> decrement the value of id by <number>
x-=10
id*=<number> multiply the value of id by <number>
x*=50
id*=<number> divide the value of id by <number>
x/=100
Addition id=<id> + number or <id>
tx=10
spacing=1.2
sx=tx-10
vx=tx+spacing
Subtraction id=<id> - number or <id>
a=x-10
Muliplication id=<id> * number or <id>
a=x*10
Division id=<id> / number or <id>
a=x/10
Modulo id=<id> % number or <id>
a=x%10
Assign (x,y) coordinates to the specified identifier.
The x coordinate is id_x and the y coordinate is id_y.
The expression with the parentheses may be a constant, variable or binary expression.
This code:
a=40
b=40
c=20
p0=(50,50)
p1=(a,b)
p2=(a+c,b)
p3=(a+c,b+c)
p4=(a,b+c)
circle p0_x p0_x 3
line p1_x p1_y p2_x p2_y 0.2 "blue"
line p2_x p2_y p3_x p3_y 0.2 "red"
line p3_x p3_y p4_x p4_y 0.2 "green"
line p4_x p4_y p1_x p1_y 0.2 "orange"
makes this:
x=polarx cx cy r theta
y=polary cx cy r theta
Return the polar coordinate given the center at (cx, cy), radius r, and angle theta (in degrees)
p=polar cx cy r theta
Return the polar coordinates (p_x) and (p_y) given the center at (cx, cy), radius r, and angle theta (in degrees)
a=area d
c=area a+b
return the circular area, a for the diameter d.
Assign a string variable with formatted text (using package fmt floating point format strings)
w1=10
w2=20+100
s0=format "Widget 1: %.2f" w1
s1=format "Widget 2: %.3f" w2
st=format "Total Widgets: %v" s1+w2
x=random min max
assign a random number in the specified range
decksh supports these math functions:
- cosine
- sine
- square root
- tangent
return the coine of the number of expression (id or binary operation)
a=4
b=10
x=cosine 4
x=cosine a+b
x=cosine b
return the sine of the number of expression (id or binary operation)
a=4
b=10
x=sine 4
x=sine a+b
x=sine b
return the square root of the number of expression (id or binary operation)
a=4
b=10
x=sqrt 4
x=sqrt a+b
x=sqrt b
return the square root of the number of expression (id or binary operation)
a=4
b=10
x=tangent 4
x=tangent a+b
x=tangent b
x=vmap v vmin vmax min max
For value v, map the range vmin-vmax to min-max.
x=substr string begin end
assigns a substring given beginning and ending indicies.
- may be used as a shorthand for the beginning and end.
s="hello, world"
a=substr s - - // a="hello, world"
b=substr s - 4 // b="hello"
c=substr s 7 - // c="world"
d=substr s 3 8 // d="lo, wo"
e=substr "This is a test" 5 8 // e="is a"
Loop over statements, with x starting at begin, ending at end with an optional increment (if omitted the increment is 1).
Substitution of x will occur in statements.
for x=begin end [increment]
statements
efor
Loop over statements, with x ranging over the contents of items within [].
Substitution of x will occur in statements.
for x=["abc" "def" "ghi"]
statements
efor
Loop over statements, with x ranging over the contents "file".
Substitution of x will occur in statements.
for x="file"
statements
efor
Specify the conditional execution of decksh statements with if condition, else and eif. The else block is optional. The values for v1 and v2 may be either numbers of strings. (For strings only == and != apply). The conditions are:
if v1 condition v2
where condition is:
== or eq equals if x == y
!= or ne not equals if x != y
< or lt less than if x > y
> or gt greater than if x < y
>= or ge greater than or equal if x >= y
<= or ge less than or equal if x <= y
>< or bt between if x >< y z
For example:
x=10
y=20
if x > y
text "x is greater than y" x y 5
else
text "x is not greater than y" x y 5
eif
The else block may be omitted:
if x < 10
text "x is less than 10" x y 5
eif
For strings:
c1="red"
c2="blue"
if c1 != c2
text "red is not blue" 50 50 2
eif
include "file"
places the contents of "file" inline.
Functions have a defined name and arguments, and are specifed with statements between the def and edef keywords
def name arg1 arg2 ... argn
statements
edef
Functions may be imported once, and then called by name.
For example, given a file redcircle.dsh:
def redcircle X Y
circle X Y 10 "red"
edef
which is referenced:
import "redcircle.dsh"
x=50
y=50
x2=x-20
y2=y+20
redcircle x y
redcircle x2 y2
makes:
Functions may also be called with the func keyword:
func "file" arg1 ... argn
For example, given a file "ftest.dsh"
def ftest funx funy funs funt
funs*=2
ctext funt funx funy funs
edef
calling the function:
func "ftest.dsh" 50 30 2.5 "hello"
produces:
funx=50
funy=30
funs=5.0
funt="hello"
ctext "hello" 50 30 5.0
data "foo.d"
uno 100
dos 200
tres 300
edata
makes a file named foo.d with the lines between data and edata.
grid "file.dsh" x y xskip yskip limit
The first file argument ("file.dsh" above) specifies a file with decksh commands; each item in the file must include the arguments "x" and "y". Normal variable substitution occurs for other arguments. For example if the contents of file.dsh has six items:
circle x y 5
circle x y 10
circle x y 15
square x y 5
square x y 10
square x y 15
The line:
grid "file.dsh" 10 80 20 30 50
creates two rows: three circles and then three squares
x, y specify the beginning location of the items, xskip is the horizontal spacing between items.
yinternal is the vertical spacing between items and limit the the horizontal limit. When the limit is reached,
a new row is created.
Left, centered, end, or block-aligned text or file contents (x and y are the text's reference point), with optional font ("sans", "serif", "mono", or "symbol"), color and opacity.
text "text" x y size [font] [color] [opacity] [link]
btext "text" x y size [font] [color] [opacity] [link]
ctext "text" x y size [font] [color] [opacity] [link]
etext "text" x y size [font] [color] [opacity] [link]
textblock "text" x y width size [font] [color] [opacity] [link]
textblockfile "filename" x y width size [font] [color] [opacity] [link]
Text rotated along the specified angle (in degrees)
rtext "text" x y angle size [font] [color] [opacity] [link]
Text on an arc centered at (x,y), with specified radius, between begin and ending angles (in degrees).
if the beginning angle is less than the ending angle the text is rendered counter-clockwise.
if the beginning angle is greater than the ending angle, the text is rendered clockwise.
arctext "text" x y radius begin-angle end-angle size [font] [color] [opacity] [link]
Place the contents of "filename" at (x,y). Place the contents of "filename" in gray box, using a monospaced font.
textfile "filename" x y size [font] [color] [opacity] [linespacing]
textcode "filename" x y width size [color]
Plain and captioned, with optional scales, links and caption size. (x, y) is the center of the image,
and width and height are the image dimensions in pixels.
image "file" x y width height [scale] [link]
cimage "file" "caption" x y width height [scale] [link] [size]
(plain, bulleted, numbered, centered). Optional arguments specify the color, opacity, line spacing, link and rotation (degrees)
list x y size [font] [color] [opacity] [linespacing] [link] [rotation]
blist x y size [font] [color] [opacity] [linespacing] [link] [rotation]
nlist x y size [font] [color] [opacity] [linespacing] [link] [rotation]
clist x y size [font] [color] [opacity] [linespacing] [link] [rotation]
li "text"
elist
Rectangles, ellipses, squares, circles: specify the center location (x, y) and
dimensions (w,h) with optional color and opacity.
The default color and opacity is gray, 100%. In the case of the acircle keyword, the a argument
is the area, not the diameter.
rect x y w h [color] [opacity]
ellipse x y w h [color] [opacity]
square x y w [color] [opacity]
circle x y w [color] [opacity]
acircle x y a [color] [opacity]
Rounded rectangles are similar, with the added radius for the corners: (solid colors only)
rrect x y w h r [color]
For polygons, specify the x and y coordinates as a series of numbers, with optional color and opacity.
polygon "xcoords" "ycoords" [color] [opacity]
Note that the coordinates may be either discrete:
polygon "10 20 30" "50 60 50"
or use substitution:
x1=10
x2=20
x3=30
y1=50
y2=y1+10
y3=y1
polygon "x1 x2 x3" "y1 y2 y3"
A combination of constants and substitution is also allowed.
polygon "20 x2 30" "50 y2 50"
Polyline is similar to polygon, except line segments are used instead of a filled polygon, and you may specify a line width.
polyline "xcoords" "ycoords" [lw] [color] [opacity]
For lines, specify the coordinates for the beginning (x1,y1) and end points (x2, y2).
For horizontal and vertical lines specify the initial point and the length.
Line thickness, color and opacity are optional, with defaults (0.2, gray, 100%).
A "pill" shape has is a horizontal line with rounded ends.
line x1 y1 x2 y2 [size] [color] [opacity]
hline x y length [size] [color] [opacity]
vline x y length [size] [color] [opacity]
pill x w length size [color]
Curve is a quadratic Bezier curve: specify the beginning location (bx, by),
the control point (cx, cy), and ending location (ex, ey).
For arcs, specify the location of the center point (x,y), the width and height, and the beginning and ending angles (in degrees). Line thickness, color and opacity are optional, with defaults (0.2, gray, 100%).
curve bx by cx cy ex ey [size] [color] [opacity]
arc x y w h a1 a2 [size] [color] [opacity]
To make n-sided stars, use the "star" keyword: (x,y) is the center of the star,
np is the number of points, and inner and outer are the sizes of
the inner and outer points, respectively.
star x y np inner outer [color] [opacity]
Arrows with optional linewidth, width, height, color, and opacity.
Default linewidth is 0.2, default arrow width and height is 3, default color and opacity is gray, 100%.
The curve variants use the same syntax for specifying curves.
arrow x1 y1 x2 y2 [linewidth] [arrowidth] [arrowheight] [color] [opacity]
lcarrow bx by cx cy ex ey [linewidth] [arrowidth] [arrowheight] [color] [opacity]
rcarrow bx by cx cy ex ey [linewidth] [arrowidth] [arrowheight] [color] [opacity]
ucarrow bx by cx cy ex ey [linewidth] [arrowidth] [arrowheight] [color] [opacity]
dcarrow bx by cx cy ex ey [linewidth] [arrowidth] [arrowheight] [color] [opacity]
Left, right, up and down-facing braces.
(x, y) is the location of the point of the brace, (aw, ah) are width and height of the braces's
end curves; linewidth, color and opacity are optional (defaults are 0.2, gray, 100%)
lbrace x y height aw ah [linewidth] [color] [opacity]
rbrace x y height aw ah [linewidth] [color] [opacity]
ubrace x y width aw ah [linewidth] [color] [opacity]
dbrace x y width aw ah [linewidth] [color] [opacity]
Left, right, up and down-facing brackets.
(x, y) is the location of the center of the bracket.
For left and right-facing brackets, width is the size of the top and bottom portions, and height is the span of the bracket.
For upward and downward-facing brackets, width is the span of of bracket, and height is the size of the
left and right portions. linewidth, color and opacity are optional (defaults are 0.2, gray, 100%)
lbracket x y width height [linewidth] [color] [opacity]
rbracket x y width height [linewidth] [color] [opacity]
ubracket x y width height [linewidth] [color] [opacity]
dbracket x y width height [linewidth] [color] [opacity]
Run the dchart command with the specified arguments.
dchart [args]
Show a colored legend
legend "text" x y size [font] [color]
