翻訳と辞書 Words near each other ・ Liangxiang University Town Station ・ Liangxiang University Town West Station ・ Liangxiang, Beijing ・ Liangxiangnanguan Station ・ Liangxidaqiao Station ・ Liangxiongdiyu ・ Liangyuan District ・ Liangzhou District ・ Liangzhu ・ Liangzhu (town) ・ Liangzhu culture ・ Liangzhu Museum ・ Liangzhu Station ・ Liangzi Lake ・ Liangzihu District ・ Liang–Barsky algorithm ・ Lianhang Road Station ・ Lianhe ・ Lianhe Wanbao ・ Lianhe Zaobao ・ Lianhu District ・ Lianhu railway station ・ Lianhua ・ Lianhua County ・ Lianhua Dam ・ Lianhua Film Company ・ Lianhua North Station ・ Lianhua Road Station ・ Lianhua Supermarket ・ Lianhua Symphony Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Liang–Barsky algorithm ： ウィキペディア英語版 Liang–Barsky algorithm In computer graphics, the Liang–Barsky algorithm (named after You-Dong Liang and Brian A. Barsky) is a line clipping algorithm. The Liang–Barsky algorithm uses the parametric equation of a line and inequalities describing the range of the clipping window to determine the intersections between the line and the clipping window. With these intersections it knows which portion of the line should be drawn. This algorithm is significantly more efficient than Cohen–Sutherland.The idea of the Liang-Barsky clipping algorithm is to do as much testing as possible before computing line intersections. Consider first the usual parametric form of a straight line: :$x\; =\; x\_0\; +\; u\; (x\_1\; -\; x\_0)\; =\; x\_0\; +\; u\; \backslash Delta\; x\backslash ,\backslash !$ :$y\; =\; y\_0\; +\; u\; (y\_1\; -\; y\_0)\; =\; y\_0\; +\; u\; \backslash Delta\; y\backslash ,\backslash !$ A point is in the clip window, if :$x\_\}\backslash ,\backslash !$ and :$y\_\}\backslash ,\backslash !$, which can be expressed as the 4 inequalities :$u\; p\_k\; \backslash le\; q\_k,\; \backslash quad\; k\; =\; 1,\; 2,\; 3,\; 4\backslash ,\backslash !$, where :$p\_1\; =\; -\backslash Delta\; x\; ,\; q\_1\; =\; x\_0\; -\; x\_\}\; -\; x\_0\backslash ,\backslash !$ (right) :$p\_3\; =\; -\backslash Delta\; y\; ,\; q\_3\; =\; y\_0\; -\; y\_\backslash text\backslash ,\backslash !$ (bottom) :$p\_4\; =\; \backslash Delta\; y\; ,\; q\_4\; =\; y\_\backslash text\; -\; y\_0\backslash ,\backslash !$ (top) To compute the final line segment: # A line parallel to a clipping window edge has $p\_k\; =\; 0$ for that boundary. # If for that $k$, , the line is completely outside and can be eliminated. # When the line proceeds outside to inside the clip window and when $p\_k\; >\; 0$, the line proceeds inside to outside. # For nonzero $p\_k$, $u\; =\; \backslash frac$ gives the intersection point. # For each line, calculate $u\_1$ and $u\_2$. For $u\_1$, look at boundaries for which (i.e. outside to inside). Take $u\_1$ to be the largest among $\backslash left\backslash \; \backslash right\backslash \}$. For $u\_2$, look at boundaries for which $p\_k\; >\; 0$ (i.e. inside to outside). Take $u\_2$ to be the minimum of $\backslash left\backslash \; \backslash right\backslash \}$. If $u\_1\; >\; u\_2$, the line is outside and therefore rejected. ==See also== Algorithms used for the same purpose: * Cyrus–Beck * Nicholl–Lee–Nicholl * Fast-clipping 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Liang–Barsky algorithm」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.