Documentation
¶
Overview ¶
Package canvas defines the Canvas interface, the BufferBasedCanvas interface, and the ByteColorBuffer type which implements it.
Index ¶
- type BufferBasedCanvas
- type ByteColorBuffer
- func (cnv *ByteColorBuffer) At(x, y int) (color.Color, error)
- func (cnv *ByteColorBuffer) BucketFill(x, y int, c color.Color) error
- func (cnv *ByteColorBuffer) Dimensions() (width, height int)
- func (cnv *ByteColorBuffer) DrawLine(x1, y1, x2, y2 int) error
- func (cnv *ByteColorBuffer) DrawRect(x1, y1, x2, y2 int) error
- func (cnv *ByteColorBuffer) Pixels() []color.ByteColor
- func (cnv *ByteColorBuffer) Set(x, y int, c color.Color) error
- type Canvas
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type BufferBasedCanvas ¶
type BufferBasedCanvas interface {
// Canvas is a super-interface of BufferBasedCanvas.
Canvas
// At returns the color of the pixel at (x, y).
//
// Errors
//
// common.ErrPointOutsideCanvas:
// Will be returned if (x, y) is outside the canvas.
//
At(x, y int) (color.Color, error)
// Set sets the color of the pixel at (x, y).
//
// Errors
//
// common.ErrPointOutsideCanvas:
// Will be returned if (x, y) is outside the canvas.
//
// common.ErrColorTypeNotSupported:
// Will be returned if c is not supported by the canvas.
//
Set(x, y int, c color.Color) error
}
BufferBasedCanvas is a Canvas based on a buffer of color.Color.
type ByteColorBuffer ¶
type ByteColorBuffer struct {
// contains filtered or unexported fields
}
ByteColorBuffer is a canvas based on a buffer of color.ByteColor. It implements the Canvas interface and the BufferBasedCanvas interface.
func NewByteColorBuffer ¶
func NewByteColorBuffer(width, height int, bgColor, fgColor color.ByteColor) (*ByteColorBuffer, error)
NewByteColorBuffer returns a new ByteColorBuffer.
Errors ¶
common.ErrWidthOrHeightNotPositive: Will be returned if width <= 0, or height <= 0.
func (*ByteColorBuffer) At ¶
func (cnv *ByteColorBuffer) At(x, y int) (color.Color, error)
At returns the color of the pixel at (x, y).
Errors ¶
common.ErrPointOutsideCanvas: Will be returned if (x, y) is outside the canvas.
func (*ByteColorBuffer) BucketFill ¶
func (cnv *ByteColorBuffer) BucketFill(x, y int, c color.Color) error
BucketFill fills the area enclosing (x, y). The pixels connecting to (x, y) having the same color as that at (x, y) are replaced by c.
Errors ¶
common.ErrPointOutsideCanvas: Will be returned if (x, y) is outside the canvas.
common.ErrColorTypeNotSupported: Will be returned if c is not supported by the canvas.
func (*ByteColorBuffer) Dimensions ¶
func (cnv *ByteColorBuffer) Dimensions() (width, height int)
Dimensions returns the width and height.
func (*ByteColorBuffer) DrawLine ¶
func (cnv *ByteColorBuffer) DrawLine(x1, y1, x2, y2 int) error
DrawLine draws a horizontal or vertical line.
Errors ¶
common.ErrPointOutsideCanvas: Will be returned if (x1, y1) or (x2, y2) is outside the canvas.
common.ErrLineNotHorizontalOrVertical: Will be returned if the line is not horizontal or vertical.
func (*ByteColorBuffer) DrawRect ¶
func (cnv *ByteColorBuffer) DrawRect(x1, y1, x2, y2 int) error
DrawRect draws a rectangle.
Errors ¶
common.ErrPointOutsideCanvas: Will be returned if (x1, y1) or (x2, y2) is outside the canvas.
func (*ByteColorBuffer) Pixels ¶
func (cnv *ByteColorBuffer) Pixels() []color.ByteColor
Pixels returns the underlying pixel buffer.
func (*ByteColorBuffer) Set ¶
func (cnv *ByteColorBuffer) Set(x, y int, c color.Color) error
Set sets the color of the pixel at (x, y).
Errors ¶
common.ErrPointOutsideCanvas: Will be returned if (x, y) is outside the canvas.
common.ErrColorTypeNotSupported: Will be returned if c is not supported by the canvas.
type Canvas ¶
type Canvas interface {
// Dimensions returns the width and height.
Dimensions() (int, int)
// DrawLine draws a horizontal or vertical line.
//
// Errors
//
// common.ErrPointOutsideCanvas:
// Will be returned if (x1, y1) or (x2, y2) is outside the canvas.
//
// common.ErrLineNotHorizontalOrVertical:
// Will be returned if the line is not horizontal or vertical.
//
DrawLine(x1, y1, x2, y2 int) error
// DrawRect draws a rectangle.
//
// Errors
//
// common.ErrPointOutsideCanvas:
// Will be returned if (x1, y1) or (x2, y2) is outside the canvas.
//
DrawRect(x1, y1, x2, y2 int) error
// BucketFill fills the area enclosing (x, y). The pixels connecting to
// (x, y) having the same color as that at (x, y) are replaced by c.
//
// Errors
//
// common.ErrPointOutsideCanvas:
// Will be returned if (x, y) is outside the canvas.
//
// common.ErrColorTypeNotSupported:
// Will be returned if c is not supported by the canvas.
//
BucketFill(x, y int, c color.Color) error
}
Canvas is a finite rectangular grid which allows several drawing operations. The coordinate system is zero-based.
Source Files