class Chitra::Context

• Chitra::Context
• Reference
• Object

Included Modules

• Chitra::ShapeProperties
• Chitra::TextProperties

Defined in:

Instance Method Summary

• #background(r, g, b, a = 1.0)

  Fill background color ctx = Chitra.new # white background ctx.background 1, 0, 0

• #background(hexcol : String)

  Fill background color(Hex Color) ctx = Chitra.new # white background ctx.background "#ffffff"

• #background(gray, a = 1.0)

  Fill background color(Gray scale) ctx = Chitra.new # white background ctx.background 1

• #composite(op : String)

  Apply Composite ctx.group_start ctx.rect 10, 10, 100, 100 ctx.composite "in" ctx.rect 50, 50, 100, 100 ctx.group_end Other available Composite options are: Clear, Source, Over, In, Out, Atop, Dest, DestOver, DestIn, DestOut, DestAtop, Xor, Add, Saturate, Multiply, Screen, Overlay, Darken, Lighten, ColorDodge, ColorBurn, HardLight, SoftLight, Difference, Exclusion, HslHue, HslSaturation, HslColor, HslLuminosity

• #debug : Bool
• #debug=(debug : Bool)
• #elements : Array(Chitra::Element)
• #enable_debug

  Enable debug messages to verify if any property applied to an element is not maching ctx = Chitra.new ctx.enable_debug

• #fill(r, g, b, a = 1.0)

  Set fill color.

• #fill(hexcol : String)

  Set fill color in hex format.

• #fill(gray, a = 1.0)

  Set fill color.

• #fill_opacity(a)

  Set fill opacity.

• #font(font_name, font_size)

  Set Font family and size ctx.font "Times", 30

• #font_size(font_size)

  Set Font size ctx.font_size 30

• #font_weight(wt)

  Set Font weight ctx.font_weight "Heavy"

• #group_end

  End a Group ctx.group_start ctx.rect 10, 10, 100, 100 ctx.composite "in" ctx.rect 50, 50, 100, 100 ctx.group_end

• #group_start

  Start a Group ctx.group_start ctx.rect 10, 10, 100, 100 ctx.composite "in" ctx.rect 50, 50, 100, 100 ctx.group_end

• #grouped(&block)

  Grouped code run as block ctx.grouped do ctx.rect 10, 10, 100, 100 ctx.composite "In" ctx.rect 50, 50, 100, 100 end

• #height

  Get height of the canvas # width height ctx = Chitra.new 1600, 900 puts ctx.height # 900

• #hyphen_char(value : String)

  Set Hyphenation char.

• #hyphenation(value : Bool)

  Enable/Disable text hyphenation.

• #image(path, x, y)

  Draw image ctx = Chitra.new ctx.image "logo.png", 100, 100

• #image_height(path)

  Get height of the image ctx = Chitra.new h = ctx.image_height "logo.png"

• #image_size(path)

  Get width and height of the image ctx = Chitra.new w, h = ctx.image_size "logo.png"

• #image_width(path)

  Get width of the image ctx = Chitra.new w = ctx.image_width "logo.png"

• #line(x1, y1, x2, y2)

  Draw a line ctx = Chitra.new x y w h ctx.line 100, 100, 500, 500

• #line_cap(value)

  Set Line cap style Allowed values are butt, round and square.

• #line_dash(values : Array(Int32), offset = 0)

  Set line dash pattern.

• #line_dash(*values, offset = 0)

  Set line dash pattern.

• #line_height(value)
• #line_join(value)

  Set Line join style Possible values are: miter, round, bevel.

• #markup(txt, x, y)

  Draw text for given x and y values.

• #markup_box(txt, x, y, w, h = 0.0)
• #new_drawing

  Reset the drawing to clean and empty canvas ctx = Chitra.new ctx.fill 0 ctx.rect 0, 0, width, height ctx.save "slide1.png" ctx.new_drawing ctx.fill 0, 0, 1 ctx.rect 0, 0, width, height ctx.save "slide2.png"

• #new_page

  Creates a new page.

• #no_fill

  Disable fill ctx.no_fill

• #no_stroke

  Disable Stroke.

• #oval(x, y, w = 2.0, h = 0.0)

  Draw oval shape ctx = Chitra.new x y w h ctx.oval 100, 100, 500, 500

• #polygon(points : Array(Float64), close = true)

  Draw polygon shape.

• #polygon(*points, close = true)

  Draw polygon shape.

• #rainbow(txt : String | Array(String), x, y, colors = RAINBOW_COLORS, join_str = "")
• #rainbow_box(txt : String | Array(String), x, y, w, h = 0.0, colors = RAINBOW_COLORS, join_str = "")
• #rect(x, y, w, h = 0.0)

  Draw rectangle shape ctx = Chitra.new x y w h ctx.rect 100, 100, 500, 500

• #restore_state(saved_context)

  Restore Context state ctx.restore_state

• #rotate(angle, center_x = 0, center_y = 0)

  Rotate the canvas in clockwise to given angle.

• #save(file : String)

  Save the output to a file.

• #save_state(saved_context)

  Save Context state ctx.save_state ctx.fill 0, 0, 1

• #saved_state(&block)

  Use Saved state as block that applies save_state and restore_state automatically.

• #scale(scale_x, scale_y = 0)

  Scale the canvas with the given x and y scale factors.

• #size : Chitra::Size
• #size=(size : Chitra::Size)
• #stroke(r, g, b, a = 1.0)

  Set Stroke color(Gray scale).

• #stroke(hexcol : String)

  Set Stroke color in hex format.

• #stroke(gray, a = 1.0)

  Set stroke/line color(Gray scale).

• #stroke_opacity(a)

  Set stroke opacity.

• #stroke_width(value : Int32)

  Set Stroke/Line width.

• #text(txt, x, y)

  Draw text for given x and y values.

• #text_align(value : String)

  Set Text align for text boxes ctx.text_align "center"

• #text_box(txt, x, y, w, h = 0.0)
• #translate(x, y)

  Translate the canvas to given x and y ctx = Chitra.new ctx.translate 100, 100 ctx.rect 0, 0, 500, 500

• #width

  Get width of the canvas # width height ctx = Chitra.new 1600, 900 puts ctx.width # 1600

Instance Method Detail

ctx = Chitra.new
# white background
ctx.background 1, 0, 0

ctx = Chitra.new
# white background
ctx.background "#ffffff"

ctx = Chitra.new
# white background
ctx.background 1

ctx.group_start
ctx.rect 10, 10, 100, 100
ctx.composite "in"
ctx.rect 50, 50, 100, 100
ctx.group_end

ctx = Chitra.new
ctx.enable_debug

#        r  g  b
ctx.fill 0, 0, 1

# Fill with 50% opacity
r g b a
ctx.fill 0, 0, 1, 0.5

# Black color
#        hex_color
ctx.fill "#000000"

# White color
ctx.fill "#ffffff"

# Fill black with 50% opacity
# 00 - 0% and FF - 100% opacity
gray a
ctx.fill "#00000080"

# Black color
#        gray
ctx.fill 0

# White color
ctx.fill 1

# Fill black with 50% opacity
gray a
ctx.fill 0, 0.5

# 50% Opacity
#                opacity
ctx.fill_opacity 0.5

ctx.font "Times", 30

ctx.font_size 30

ctx.font_weight "Heavy"

ctx.group_start
ctx.rect 10, 10, 100, 100
ctx.composite "in"
ctx.rect 50, 50, 100, 100
ctx.group_end

ctx.group_start
ctx.rect 10, 10, 100, 100
ctx.composite "in"
ctx.rect 50, 50, 100, 100
ctx.group_end

ctx.grouped do
  ctx.rect 10, 10, 100, 100
  ctx.composite "In"
  ctx.rect 50, 50, 100, 100
end

#                         width height
ctx = Chitra.new 1600, 900
puts ctx.height # 900

ctx.hyphen_char "*"

ctx.hyphenation true

ctx = Chitra.new
ctx.image "logo.png", 100, 100

ctx = Chitra.new
h = ctx.image_height "logo.png"

ctx = Chitra.new
w, h = ctx.image_size "logo.png"

ctx = Chitra.new
w = ctx.image_width "logo.png"

ctx = Chitra.new
x y w h
ctx.line 100, 100, 500, 500

ctx.line_cap "round"
ctx.line 100, 100, 500, 100

ctx.line_dash [2]

ctx.line_dash [2, 4, 10]

ctx.line_dash [2, 4, 10], offset: 1

ctx.line_dash 2

ctx.line_dash 2, 4, 10

ctx.line_dash 2, 4, 10, offset: 1

ctx.stroke_width 14
ctx.line_join "round"
ctx.rect 100, 100, 500, 500

markup "Hello <b>World</b>", 100, 100

ctx = Chitra.new
ctx.fill 0
ctx.rect 0, 0, width, height
ctx.save "slide1.png"
ctx.new_drawing
ctx.fill 0, 0, 1
ctx.rect 0, 0, width, height
ctx.save "slide2.png"

ctx = Chitra.new 200
ctx.scale 2
ctx.rect 40, 40, 40, 40
ctx.new_page
ctx.rect 40, 40, 40, 40

ctx.no_fill

ctx.stroke_width 0
# OR
ctx.no_stroke

ctx = Chitra.new
x y w h
ctx.oval 100, 100, 500, 500

ctx = Chitra.new
x y w h
ctx.polygon [50, 450, 50, 50, 450, 50, 100, 100], close: true

ctx = Chitra.new
x y w h
ctx.polygon 50, 450, 50, 50, 450, 50, 100, 100, close: true

ctx = Chitra.new
x y w h
ctx.rect 100, 100, 500, 500

ctx.restore_state

ctx = Chitra.new 200
ctx.rotate 45
ctx.rect 40, 40, 40, 40

ctx = Chitra.new 200
ctx.rotate 45, 100, 100
ctx.rect 50, 50, 100, 100

ctx = Chitra.new
#        filename
ctx.save "hello.png"

ctx.save_state
ctx.fill 0, 0, 1

ctx.fill 1, 0, 0
ctx.saved_state do
  ctx.fill 0, 0, 1
  # Blue rect
  ctx.rect 100, 100, 200, 200
end
# Red Rect
ctx.rect 200, 200, 200, 200

ctx = Chitra.new 200
ctx.scale 2
ctx.rect 40, 40, 40, 40

ctx = Chitra.new 200
ctx.scale 2, 1
ctx.rect 40, 40, 40, 40

#          r  g  b
ctx.stroke 0, 0, 1

# Stroke with 50% opacity
r g b a
ctx.stroke 0, 0, 1, 0.5

# Black color
#          hex_color
ctx.stroke "#000000"

# White color
ctx.stroke "#ffffff"

# Fill black with 50% opacity
# 00 - 0% and FF - 100% opacity
ctx.stroke "#00000080"

# Black color
#          gray
ctx.stroke 0

# White color
ctx.stroke 1

# Fill black with 50% opacity
gray a
ctx.stroke 0, 0.5

# 50% Opacity
#                  opacity
ctx.stroke_opacity 0.5

ctx.stroke_width 10

text "Hello World", 100, 100

ctx.text_align "center"

ctx = Chitra.new
ctx.translate 100, 100
ctx.rect 0, 0, 500, 500

#                         width height
ctx = Chitra.new 1600, 900
puts ctx.width # 1600