Class: Iup::Canvas

Inherits:
Widget show all
Includes:
ButtonCallback, DragDropAttributes, ScrollBarAttributes
Defined in:
lib/wrapped/canvas.rb

Overview

A Canvas is a working area for the application.

Many methods working on the Canvas are drawn from the CD library: webserver2.tecgraf.puc-rio.br/cd/

In this example, notice how the dialog is mapped, the canvas initialised, and finally the dialog is shown.

mainloop do
  cnv = Canvas.new do
    rastersize '300x200'
    action ->(x, y){ # called on redraw: (x,y) refer to scrollbar positions, if used
      clear
      foreground CD_BLUE
      box 10, 100, 10, 100
      foreground CD_RED
      rectangle 10, 100, 10, 100
      text 200, 180, 'hello from Ruby'
      DEFAULT
    }
  end

  dlg = Dialog.new VBox.new(cnv){ margin '10x10' } do
    title 'IupCanvas + Canvas Draw'
    size '350x220'
  end.map

  cnv.init # this has to be done after mapping the dialog

  dlg.show
end

Attributes

canfocus

Enables the control to gain focus. Values ‘yes’ / ‘no’.

cursor

Defines the mouse shape / cursor for the canvas.

drawsize

Size of the drawing area in pixels, as “widthxheight”.

expand

Allows canvas to fill available space in indicated direction. Values ‘no’ / ‘horizontal’ / ‘vertical’ / ‘yes’.

padding

Margin in x and y directions, value as “mxn”.

position

read-only returns position in pixels within client window as “x,y”.

rastersize

Size of the canvas, in pixels, value as “widthxheight”.

screenposition

read-only returns position in pixels on screen

scrollbar

Selects ‘no’ / ‘horizontal’ / ‘vertical’ / ‘yes’ (for both) scrollbars.

tip

Tooltip string.

Instance Attribute Summary

Attributes inherited from Widget

#handle

Instance Method Summary collapse

Methods included from ButtonCallback

#button_cb

Methods included from ScrollBarAttributes

#dx, #dy, #linex, #liney, #posx, #posy, #scroll_cb, #xmax, #xmin, #ymax, #ymin

Methods included from AttributeBuilders

#define_attribute, #define_id_attribute, #define_id_readonly, #define_id_writeonly, #define_property_attribute, #define_property_writeonly, #define_readonly, #define_writeonly

Methods included from DragDropAttributes

#dragbegin_cb, #dragdata_cb, #dragdatasize_cb, #dragend_cb, #dropdata_cb, #dropmotion_cb

Methods inherited from Widget

#assign_handle, #enterwindow_cb, #getfocus_cb, #help_cb, #k_any, #killfocus_cb, #leavewindow_cb, #map_cb, #open_controls, #unmap_cb

Methods included from CallbackSetter

#define_callback

Constructor Details

#initialize(handle = IupLib.IupCanvas(''), &block) ⇒ Canvas

Creates an instance of the canvas.

handle

an optional Canvas handle.

block

optional block to set up Canvas attributes.



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# File 'lib/wrapped/canvas.rb', line 58

def initialize handle = IupLib.IupCanvas(''), &block
  @handle = handle

  # run any provided block on instance, to set up further attributes
  self.instance_eval &block if block_given?
end

Instance Method Details

#action(callback) ⇒ Object

Action generated when the canvas needs to be redrawn. Action takes a callback which accepts 2 arguments (posx, posy). posx, posy are the position of the horizontal and vertical thumbs of the scrollbar.



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# File 'lib/wrapped/canvas.rb', line 380

def action callback
  unless callback.arity == 2
    raise ArgumentError, 'action must take 2 arguments: (posx, posy)'
  end
  cb = Proc.new do |ih, posx, posy|
    callback.call posx, posy
  end
  define_callback cb, 'ACTION', :ff_i
end

#activate ⇒ Object

call to activate canvas. (Not usually needed - depends on driver.)



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# File 'lib/wrapped/canvas.rb', line 95

def activate
  CdLib.cdCanvasActivate @canvas
end

#arc(xc, yc, w, h, angle1, angle2) ⇒ Object

Draws an arc of an ellipse - a pie-shaped slice. Angles are in degrees, counterclockwise.



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# File 'lib/wrapped/canvas.rb', line 229

def arc xc, yc, w, h, angle1, angle2
  CdLib.cdCanvasArc @canvas, xc, yc, w, h, angle1, angle2
end

#background(colour = CD_QUERY) ⇒ Object

Sets the background colour, if a value is given, else returns current value.

Colour may be one of:

  • string, in form “RR GG BB”

  • colour constant, e.g. CD_BLACK, as listed in Iup



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# File 'lib/wrapped/canvas.rb', line 142

def background colour=CD_QUERY
  case colour
  when String # assume in form 'RR GG BB'
    r, g, b = colour.split(' ').collect &:to_i
    CdLib.cdCanvasBackground @canvas, CdLib.cdEncodeColor(r, g, b)
  else
    CdLib.cdCanvasBackground @canvas, colour
  end
end

#backopacity(opacity = CD_QUERY) ⇒ Object

Sets the opacity, if a value is given, else returns current value. See Iup for background opacity mode values.



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# File 'lib/wrapped/canvas.rb', line 279

def backopacity opacity=CD_QUERY
  CdLib.cdCanvasBackOpacity @canvas, opacity
end

#begin_block(mode) ⇒ Object

Begin the definition of a sequence of vertices. Valid polygon mode values are listed in Iup.



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# File 'lib/wrapped/canvas.rb', line 171

def begin_block mode
  CdLib.cdCanvasBegin @canvas, mode
end

#box(xmin, xmax, ymin, ymax) ⇒ Object

Fills a rectangle, according to current interior style.



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# File 'lib/wrapped/canvas.rb', line 259

def box xmin, xmax, ymin, ymax
  CdLib.cdCanvasBox @canvas, xmin, xmax, ymin, ymax
end

#chord(xc, yc, w, h, angle1, angle2) ⇒ Object

Fills a chord, according to current interior style. A chord is an arc of an ellipse - with the arc points connected. Angles are in degrees, counterclockwise.



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# File 'lib/wrapped/canvas.rb', line 273

def chord xc, yc, w, h, angle1, angle2
  CdLib.cdCanvasChord @canvas, xc, yc, w, h, angle1, angle2
end

#clear ⇒ Object

Clears the canvas.



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# File 'lib/wrapped/canvas.rb', line 162

def clear
  CdLib.cdCanvasClear @canvas
end

#deactivate ⇒ Object

call to deactivate canvas. (Not usually needed - depends on driver.)



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# File 'lib/wrapped/canvas.rb', line 101

def deactivate
  CdLib.cdCanvasDeactivate @canvas
end

#end_block ⇒ Object

End the definition of a sequence of vertices.



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# File 'lib/wrapped/canvas.rb', line 181

def end_block 
  CdLib.cdCanvasEnd @canvas
end

#fillmode(mode = CD_QUERY) ⇒ Object

Sets the fill mode, if a value is given, else returns current value. See Iup for fill mode values.



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# File 'lib/wrapped/canvas.rb', line 285

def fillmode mode=CD_QUERY
  CdLib.cdCanvasFillMode @canvas, mode
end

#focus_cb(callback) ⇒ Object

Called when the canvas gets or loses the keyboard focus. Callback takes a single parameter: (focus)

focus

non-zero if canvas gaining focus, else zero.



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# File 'lib/wrapped/canvas.rb', line 395

def focus_cb callback
  unless callback.arity == 1
    raise ArgumentError, 'focus_cb callback must take 1 argument, the focus'
  end
  cb = Proc.new do |ih, focus|
    callback.call focus
  end
  define_callback cb, 'FOCUS_CB', :i_i
end

#font(typeface, style, size) ⇒ Object

Sets text font.

typeface

‘Courier’, ‘Helvetica’, ‘Times’ built-in, but any known font can be used

style

see Iup for list of text styles.

size

the font height, default is 12.



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# File 'lib/wrapped/canvas.rb', line 318

def font typeface, style, size
  CdLib.cdCanvasFont @canvas, typeface, style, size
end

#foreground(colour = CD_QUERY) ⇒ Object

Sets the foreground colour, if a value is given, else returns current value.

Colour may be one of:

  • string, in form “RR GG BB”

  • colour constant, e.g. CD_BLACK, as listed in Iup



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# File 'lib/wrapped/canvas.rb', line 127

def foreground colour=CD_QUERY
  case colour
  when String # assume in form 'RR GG BB'
    r, g, b = colour.split(' ').collect &:to_i
    CdLib.cdCanvasForeground @canvas, CdLib.cdEncodeColor(r, g, b)
  else
    CdLib.cdCanvasForeground @canvas, colour
  end
end

#hatch(style = CD_QUERY) ⇒ Object

Sets the hatch style, if a value is given, else returns current value. See Iup for hatch style values.



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# File 'lib/wrapped/canvas.rb', line 297

def hatch style=CD_QUERY
  CdLib.cdCanvasHatch @canvas, style
end

#init ⇒ Object

This must be called after the widget is mapped, to create and setup the canvas.



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# File 'lib/wrapped/canvas.rb', line 67

def init
  @canvas = CdLib.cdCreateCanvas CdLib.cdContextIup, @handle
end

#interiorstyle(style = CD_QUERY) ⇒ Object

Sets the interior style, if a value is given, else returns current value. See Iup for interior style values.



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# File 'lib/wrapped/canvas.rb', line 291

def interiorstyle style=CD_QUERY
  CdLib.cdCanvasInteriorStyle @canvas, style
end

#keypress_cb(callback) ⇒ Object

Action generated when a key is pressed or released. keypress_cb takes a 2-argument callback: (character, pressed). pressed == 1 if key is pressed, pressed == 0 if key is released.



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# File 'lib/wrapped/canvas.rb', line 409

def keypress_cb callback
  unless callback.arity == 2
    raise ArgumentError, 'keypress_cb callback must take 2 arguments: (char, press)'
  end
  cb = Proc.new do |ih, char, press|
    callback.call char, press
  end
  define_callback cb, 'KEYPRESS_CB', :ii_i
end

#kill ⇒ Object

call when canvas no longer needed.



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# File 'lib/wrapped/canvas.rb', line 89

def kill
  CdLib.cdKillCanvas @canvas
end

#line(x1, y1, x2, y2) ⇒ Object

Draws a line from (x1, y1) to (x2, y2).



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# File 'lib/wrapped/canvas.rb', line 218

def line x1, y1, x2, y2
  CdLib.cdCanvasLine @canvas, x1, y1, x2, y2
end

#linecap(style = CD_QUERY) ⇒ Object

Sets linecap, if a value is given, else returns the current value. See Iup for available linecap values.



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# File 'lib/wrapped/canvas.rb', line 252

def linecap style=CD_QUERY
  CdLib.cdCanvasLineCap @canvas, style
end

#linejoin(style = CD_QUERY) ⇒ Object

Sets linejoin, if a value is given, else returns the current value. See Iup for available linejoin values.



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# File 'lib/wrapped/canvas.rb', line 246

def linejoin style=CD_QUERY
  CdLib.cdCanvasLineJoin @canvas, style
end

#linestyle(style = CD_QUERY) ⇒ Object

Sets linestyle, if a value is given, else returns the current style. See Iup for available linestyle values.



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# File 'lib/wrapped/canvas.rb', line 235

def linestyle style=CD_QUERY
  CdLib.cdCanvasLineStyle @canvas, style
end

#linewidth(width = CD_QUERY) ⇒ Object

Sets linewidth, if a pixel value is given, else returns the current width.



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# File 'lib/wrapped/canvas.rb', line 240

def linewidth width=CD_QUERY
  CdLib.cdCanvasLineWidth @canvas, width
end

#mark(x, y) ⇒ Object

Draws a mark at position (x, y).



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# File 'lib/wrapped/canvas.rb', line 199

def mark x, y
  CdLib.cdCanvasMark @canvas, x, y
end

#marksize(size = CD_QUERY) ⇒ Object

Sets the marksize, if a pixel value is given, else, returns the current value.



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# File 'lib/wrapped/canvas.rb', line 211

def marksize size=CD_QUERY
  CdLib.cdCanvasMarkSize size
end

#marktype(type = CD_QUERY) ⇒ Object

Sets the marktype, if a value is given, else returns the current value. See Iup for available marktype values.



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# File 'lib/wrapped/canvas.rb', line 205

def marktype type=CD_QUERY
  CdLib.cdCanvasMarkType @canvas, type
end

#motion_cb(callback) ⇒ Object

Action generated when the mouse is moved. Callback takes 3 arguments: (x, y, state)

x

x position of mouse

y

y position of mouse

state

status of mouse buttons and certain keyboard keys at the moment the event was generated.

– TODO: include functions, as in button_cb



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# File 'lib/wrapped/canvas.rb', line 427

def motion_cb callback
  unless callback.arity == 3
    raise ArgumentError, 'motion_cb callback must take 3 arguments: (x, y, state)'
  end
  cb = Proc.new do |ih, x, y, state|
    callback.call x, y, state
  end
  define_callback cb, 'MOTION_CB', :iis_i
end

#nativefont(font) ⇒ Object

Sets the current font.



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# File 'lib/wrapped/canvas.rb', line 323

def nativefont font
  CdLib.cdCanvasNativefont @canvas, font
end

#pathset(action) ⇒ Object

Specify action for next point on path. Valid path actions are listed in Iup.



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# File 'lib/wrapped/canvas.rb', line 187

def pathset action
  CdLib.cdCanvasPathSet @canvas, action
end

#pixel(x, y, colour) ⇒ Object

Configures pixel (x, y) with colour.



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# File 'lib/wrapped/canvas.rb', line 194

def pixel x, y, colour
  CdLib.cdCanvasPixel @canvas, x, y, colour
end

#rectangle(xmin, xmax, ymin, ymax) ⇒ Object

Draws a rectangle bounding (xmin, ymin) to (xmax, ymax).



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# File 'lib/wrapped/canvas.rb', line 223

def rectangle xmin, xmax, ymin, ymax
  CdLib.cdCanvasRect @canvas, xmin, xmax, ymin, ymax
end

#redraw ⇒ Object

redraws the underlying canvas.



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# File 'lib/wrapped/canvas.rb', line 116

def redraw
  IupLib.IupRedraw @handle
end

#resize_cb(callback) ⇒ Object

Action generated when the canvas size is changed. resize_cb a 2-argument callback: (width, height).

width

internal width of canvas (client width)

height

internal height of canvas (client height)



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# File 'lib/wrapped/canvas.rb', line 441

def resize_cb callback
  unless callback.arity == 2
    raise ArgumentError, 'resize_cb callback must take 2 arguments: (width, height)'
  end
  cb = Proc.new do |ih, width, height|
    callback.call width, height
  end
  define_callback cb, 'RESIZE_CB', :ii_i
end

#sector(xc, yc, w, h, angle1, angle2) ⇒ Object

Fills a sector, according to current interior style. A sector is an arc of an ellipse - a pie-shaped slice. Angles are in degrees, counterclockwise.



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# File 'lib/wrapped/canvas.rb', line 266

def sector xc, yc, w, h, angle1, angle2
  CdLib.cdCanvasSector @canvas, xc, yc, w, h, angle1, angle2
end

#stipple(w, h, fgbg) ⇒ Object

fgbg is a string representing the stipple pattern in binary



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# File 'lib/wrapped/canvas.rb', line 302

def stipple w, h, fgbg
  CdLib.cdCanvasStipple @canvas, w, h, fgbg
end

#text(x, y, str) ⇒ Object

Draw text str at position (x, y). Expects an ANSI-string.



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# File 'lib/wrapped/canvas.rb', line 309

def text x, y, str
  CdLib.cdCanvasText @canvas, x, y, str
end

#textalignment(alignment = CD_QUERY) ⇒ Object

Sets vertical and horizontal alignment if a value is given, else returns current value. See Iup for text alignment values.



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# File 'lib/wrapped/canvas.rb', line 330

def textalignment alignment=CD_QUERY
  CdLib.cdCanvasTextAlignment @canvas, alignment
end

#textorientation(orientation = CD_QUERY) ⇒ Object

Sets orientation angle if a value is given, else returns current value.



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# File 'lib/wrapped/canvas.rb', line 336

def textorientation orientation=CD_QUERY
  CdLib.cdCanvasTextOrientation @canvas, orientation
end

#vectortext(x, y, str) ⇒ Object

Draws str as vector text at position (x, y). Respects



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# File 'lib/wrapped/canvas.rb', line 344

def vectortext x, y, str
  CdLib.cdCanvasVectorText @canvas, x, y, str
end

#vectortext_charsize(size = CD_QUERY) ⇒ Object

If a size is given, then the font size is given that height. Otherwise, the current value is returned.



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# File 'lib/wrapped/canvas.rb', line 360

def vectortext_charsize size=CD_QUERY
  CdLib.cdCanvasVectorCharSize @canvas, size
end

#vectortext_direction(x1, y1, x2, y2) ⇒ Object

Defines the text direction using two points: (x1, y1) and (x2, y2).



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# File 'lib/wrapped/canvas.rb', line 349

def vectortext_direction x1, y1, x2, y2
  CdLib.cdCanvasVectorTextDirection @canvas, x1, y1, x2, y2
end

#vectortext_fontsize(size_x, size_y) ⇒ Object

Directly modifies the font size.



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# File 'lib/wrapped/canvas.rb', line 365

def vectortext_fontsize size_x, size_y
  CdLib.cdCanvasVectorFontSize @canvas, size_x, size_y
end

#vectortext_loadfont(filename) ⇒ Object

Replaces current vector font with that loaded from given filename. Returns the font name, or null.



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# File 'lib/wrapped/canvas.rb', line 371

def vectortext_loadfont filename
  CdLib.cdCanvasVectorFont @canvas, filename
end

#vectortext_size(width, height, str) ⇒ Object

Modifies font size so str fits within a box width x height in size.



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# File 'lib/wrapped/canvas.rb', line 354

def vectortext_size width, height, str
  CdLib.cdCanvasVectorTextSize @canvas, width, height, str
end

#vertex(x, y) ⇒ Object

Specify a vertex at position (x, y).



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# File 'lib/wrapped/canvas.rb', line 176

def vertex x, y
  CdLib.cdCanvasVertex @canvas, x, y
end

#viewport(x1, y1, x2, y2) ⇒ Object

Used to set coordinates of a viewport (the canvas coordinates).



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# File 'lib/wrapped/canvas.rb', line 106

def viewport x1, y1, x2, y2
  CdLib.wdCanvasViewport @canvas, x1, y1, x2, y2
end

#wheel_cb(callback) ⇒ Object

Action generated when the mouse wheel is rotated. wheel_cb a 4-argument callback: (delta, x, y, status).

delta

the amount the wheel was rotated in notches.

x, y

position in the canvas where the event has occurred, in pixels.

status

status of mouse buttons and certain keyboard keys at the moment the event was generated.



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# File 'lib/wrapped/canvas.rb', line 456

def wheel_cb callback
  unless callback.arity == 4
    raise ArgumentError, 'wheel_cb callback must take 4 arguments: (delta, x, y, status)'
  end
  cb = Proc.new do |ih, delta, x, y, status_ptr|
    status = FFI::Pointer.new(status_ptr).read_string
    callback.call delta, x, y, status
  end
  define_callback cb, 'WHEEL_CB', :fiis_i
end

#window(x1, y1, x2, y2) ⇒ Object

Used to set coordinates of a window (the world coordinates).



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# File 'lib/wrapped/canvas.rb', line 111

def window x1, y1, x2, y2
  CdLib.wdCanvasWindow @canvas, x1, y1, x2, y2
end

#writemode(mode = CD_QUERY) ⇒ Object

Sets the writing mode for all primitives, if a value is given. Else returns the current value. See Iup for a list of available writemode values.



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# File 'lib/wrapped/canvas.rb', line 155

def writemode mode=CD_QUERY
  CdLib.cdCanvasWriteMode @canvas, mode
end