Display API Reference


b5.Display

The Display object is a small abstraction layer around the rendering context.

Internal properties

  • canvas – The HTML5 canvas object
  • cache_ctx – Current cached object context
  • context – The canvas context

Methods

Display(canvas) – Creates an instance of the Display object

  • canvas – The HTML5 canvas that will be rendered to

getCanvasPoint(x_pos, y_pos) – Converts and x and y position to a canvas position

  • x_pos – X position
  • y_pos – Y position
  • returns an {x, y} object containing canvas point

clear() – Clears the canvas

drawPolygon(x, y, points, fill) – Draws a polygon using current context

  • x, y – Position at which to draw the polygon
  • points – An array of points that represent the polygon in form of [x1,y1,x2,y2,...]
  • fill – If true then the polygon will drawn filled otherwise outlined

drawLine(x1, y1, x2, y2) – Draws a line from x1, y1 to x2, y2 using current context

drawRect(x, y, w, h, fill) – Draws a rectangle using current context

  • x, y – Position at which to draw the rectangle
  • w – Width of the rectangle
  • h – Height of the rectangle
  • fill – If true then the polygon will drawn filled otherwise outlined

drawRoundRect(x, y, w, h, radius, fill) – Draws a rounded rectangle using current context

  • x, y – Position at which to draw the rectangle
  • w – Width of the rectangle
  • h – Height of the rectangle
  • radius – Corner radius
  • fill – If true then the polygon will drawn filled otherwise outlined

drawArc(x, y, radius, start_angle, end_angle, fill) – Draws an arc

  • x, y – Position at which to draw the arc
  • radius – Radius of the arc
  • start_angle – The angle at which to start drawing the arc in radians
  • end_angle – The angle at which to end drawing the arc in radians
  • fill – If true then the polygon will drawn filled otherwise outlined

drawAtlasImage(image, src_x, src_y, src_w, src_h, x, y, w, h) – Draws a portion of an image using current context

  • image – Source image
  • src_x, src_y – Top-left position of the sub section of the bitmap
  • src_w, src_h – Width and height of sub section of the bitmap
  • x, y – Position at which to draw the image
  • w, h – Width and height of the image drawn

drawImage(image, x, y, w, h) – Draws an image using current context

  • image – Source image
  • x, y – Position at which to draw the image
  • w, h – Width and height of the image drawn

drawText(text, x, y, filled) – Draws text using current context

  • text – Text string to draw
  • x, y – Position at which to draw the text
  • filled – If true then the text will drawn filled otherwise outlined

setTransform(m11, m12, m21, m22, dx, dy) – Sets the current transform for current context

clipRect(x, y, w, h) – Sets the current clip rect area for current context

clipArc(x, y, radius, start, end) – Sets the current clip arc area for current context

clipPolygon(points) – Sets the current clip polygon area for current context

saveContext() – Saves the current context

restoreContext() – Restores the current context

createCache() – Creates and returns a canvas that will be used for caching

setGlobalAlpha(alpha) – Sets global alpha value for current context

setGlobalCompositeOp(op) – Sets global composite operation for current context

setShadow(x, y, colour, blur) – Sets current shadow properties for current context

setShadowOff() – Turns shadows off for current context

setFillStyle(style) – Sets the fill style for the current context

setStrokeStyle(style) – Sets the stoke style for the current context

setLineWidth(width) – Sets the line width for the current context

setFont(font) – Sets the font for the current context

setTextAlign(align) – Sets the text alignment for the current context

setTextBaseline(baseline) – Sets the text baseline for the current context

setSmoothing(enable) – Sets smoothing for the current context

setCache(cache) – Sets the current cached context

 

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