Компьютерная графика, осень 2011: Растровая графика

  • Published on
    13-Apr-2017

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    Computer Graphics Support Group

    1

    URL: http://www.school30.spb.ru/cgsg/cgc/

    E-mail: CGSG@yandex.ru

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    Computer Graphics Support Group

    2

    ( ,

    )

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    Computer Graphics Support Group

    3Line

    x

    y

    (x1,y1)

    (x2,y2)

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    Computer Graphics Support Group

    4Line: Digital Differential Analyzer (DDA)

    (x,y) x2-x1

    y2-y1

    slope

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    Computer Graphics Support Group

    5Line: ( )

    x

    y

    (x1,y1)

    (x2,y2)

    (x,y)

    =

    =

    =

    =

    0),(0),(0),(

    )11(),(0)11(

    0)12()1()12()1(121

    121

    yxfyxfyxf

    dxydyxydxxdyyxfdxydyxydxxdy

    xxyyyyxxyyyy

    xxxx

    (x,y)

    (x,y)

    (x,y)

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    Computer Graphics Support Group

    6Line: ( )

    P(x,y)

    M(x+1,y+1/2)

    f(x,y) M f: f(M) > 0 N f(M)

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    Computer Graphics Support Group

    7Line: ( )

    P(x,y)

    ME(x+2,y+1/2)

    f(x,y) M f: f(M) > 0 N f(M)

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    Computer Graphics Support Group

    8Line: ( )

    P1(x1,y1)

    M0(x+1,y+1/2)

    f(x,y)

    f.

    (x1,y1)

    2

    )11()211()11(

    )211,11()( 0

    dxdy

    dxydyxydxxdy

    yxfMf

    =++

    =++=

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    Computer Graphics Support Group

    9Line: ( )

    .

    : 2f = e

    :e = 2 * dy - dx;

    e > 0

    e = e + 2 * dy - 2 *dx;

    e = e + 2 * dy

    e .

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    Computer Graphics Support Group

    10Line: ( )

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    Computer Graphics Support Group

    11Line: Fixed Point (DDA)

    Fixed Point .

    4- :

    2b 2b

    1/65536 x y fixed point,

    (x+y)

    (x-y)

    16 (x >> 16)

    : x = a

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    Computer Graphics Support Group

    12Circle

    x

    y

    R

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    Computer Graphics Support Group

    13Circle: ( )

    x

    y

    (0,R) x

    0),(0),(0),(

    yxfyxfyxf (x,y)

    (x,y)

    (x,y)

    M f: f(M) >= 0 S f(M) < 0

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    Computer Graphics Support Group

    14Circle: ( )

    P(x,y)

    M

    E

    SE MSE

    MEf(x,y)

    f(M) (E SE):

    522)(49344

    )23()2()2

    3,2()(

    32)(4144

    )21()2()2

    1,2()(4112

    )21()1()2

    1,1()(

    222

    222

    222

    222

    222

    222

    ++=++++

    =++=+=

    ++=++++

    =++=+=

    ++++

    =++=+=

    yxMfRyyxx

    RyxyxfMf

    xMfRyyxx

    RyxyxfMf

    Ryyxx

    RyxyxfMf

    NE

    E

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    Computer Graphics Support Group

    15Circle: ( )

    P(0,R)

    M0(1,R-1/2)

    f(x,y)

    SE

    E

    f. (x1,y1)

    RRRR

    RRRfMf

    =++

    =+==

    45

    411

    )21(1)2

    1,1()(22

    2220

    - . f 0 :

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    Computer Graphics Support Group

    16Circle: ( )

    :

    E SE(incrE=2*x+3 incrSE=2*(x-y)+5) .

    E, x 1 :

    incrE=incrE+2 incrSE=incrSE+2

    SE, x 1, y 1 :incrE=incrE+2 incrSE=incrSE+4

    :

    incrE=3 incrSE=5-2*R

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    Computer Graphics Support Group

    17Circle: ( )

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    Computer Graphics Support Group

    18Polygon

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    Computer Graphics Support Group

    19Flood Fill

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    Computer Graphics Support Group

    20Flood Fill

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    Computer Graphics Support Group

    21Text

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    Computer Graphics Support Group

    22Text

    0x3C

    0x46

    0x86

    0x86

    0x86

    0xFE

    0x86

    0x00

    ( )

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    Computer Graphics Support Group

    23

    . .

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