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公开(公告)号：US4371933A
公开(公告)日：1983-02-01
申请号：US194522
申请日：1980-10-06
摘要： An improved method and apparatus are disclosed for generating circular arcs of any arc length greater than zero up to and including a full circle of 360 degrees. The method and apparatus can locate nonsymmetrical closest points for noninteger radius and arc center values. The method and apparatus is capable of generating the incremental move commands for drawing an arc either in the clockwise or counter clockwise direction which is a distinct advantage when used to drive a pen type electromechanical plotter. By dividing the generation of a 360 degree arc into eight octants, only two of the original eight directions need to be considered as candidate directions toward the next integer display matrix value to be displayed. The method and apparatus employ a novel initialization which provides a simple stopping test for any circular arc of arbitrary length and direction. Only simple addition and sign testing is used to display the circular arc.
摘要翻译： 公开了一种改进的方法和装置，用于产生大于零直到并包括360度的整圆的任何弧长的圆弧。 该方法和装置可以定位非整数半径和圆弧中心值的非对称最近点。 该方法和装置能够产生用于沿顺时针或逆时针方向绘制弧的增量移动命令，这在用于驱动笔式机电绘图仪时是一个明显的优点。 通过将360度弧的生成除以八个八分圆，原始八个方向中只有两个需要被考虑作为要显示的下一个整数显示矩阵值的候选方向。 该方法和装置采用新颖的初始化，其为任意长度和方向的任何圆弧提供简单的停止测试。 仅使用简单的加法和符号测试来显示圆弧。
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2.发明授权Video graphics controller with selectable pattern features for line draws 失效视频图形控制器，具有可选图案功能，用于线条绘制
公开(公告)号：US5416897A
公开(公告)日：1995-05-16
申请号：US117485
申请日：1993-09-07
申请人： Thomas M. Albers , John V. Eberst , Darwin Fontenot , Richard L. Pyra , Mark W. Welker , Wood, Paul B. , Jack E. Bresenham
发明人： Thomas M. Albers , John V. Eberst , Darwin Fontenot , Richard L. Pyra , Mark W. Welker , Wood, Paul B. , Jack E. Bresenham
CPC分类号： G06T11/203
摘要： Circuitry for drawing lines includes a video memory for storing pixel data and circuitry for generating a sequence of addresses defining a line of pixels in the video memory. A first memory stores a sequence of pattern units corresponding to the generated sequence of addresses. A second memory stores a value indicating a current pattern unit. Writing circuitry writes to the video memory at a generated address responsive to a current pattern unit. A third memory stores a control value which is accessed by update circuitry for updating the second memory to indicate the next pattern unit. The update circuitry may selectively update the second memory to the sequential pattern unit or reset the second memory to a predetermined pattern unit.
摘要翻译： 用于绘制线的电路包括用于存储像素数据的视频存储器和用于产生定义视频存储器中的像素线的地址序列的电路。 第一存储器存储对应于所生成的地址序列的模式单元序列。 第二存储器存储指示当前图案单元的值。 写入电路响应于当前模式单元以产生的地址写入视频存储器。 第三存储器存储由更新电路访问的控制值，用于更新第二存储器以指示下一个模式单元。 更新电路可以选择性地将第二存储器更新为顺序模式单元或将第二存储器复位到预定模式单元。
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公开(公告)号：US06525733B1
公开(公告)日：2003-02-25
申请号：US08811101
申请日：1997-03-03
申请人： Thomas Michael Albers , John Vernon Eberst , Darwin Fontenot , Richard Lynn Pyra , Mark William Welker , Paul Berton Wood , Jack E. Bresenham
发明人： Thomas Michael Albers , John Vernon Eberst , Darwin Fontenot , Richard Lynn Pyra , Mark William Welker , Paul Berton Wood , Jack E. Bresenham
IPC分类号： G06T1500
CPC分类号： G06T11/203
摘要： A graphics processor uses a line draw facility to receive first and second values indicative of the coordinates of respective first and second end points of a line. The reception of the second value is sensed by the line draw facility and line data is generated responsive to the sensing of the second value.
摘要翻译： 图形处理器使用线绘制工具来接收指示线的相应第一和第二端点的坐标的第一和第二值。 第二值的接收由线条绘制设备感测，并且响应于对第二值的感测产生线数据。
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公开(公告)号：US5613054A
公开(公告)日：1997-03-18
申请号：US520040
申请日：1995-08-28
申请人： Thomas M. Albers , John V. Eberst , Darwin Fontenot , Richard L. Pyra , Mark W. Welker , Paul B. Wood , Jack E. Bresenham
发明人： Thomas M. Albers , John V. Eberst , Darwin Fontenot , Richard L. Pyra , Mark W. Welker , Paul B. Wood , Jack E. Bresenham
CPC分类号： G06T11/203
摘要： Line draw circuitry receives parameters defining first and second endpoints of a line and calculates line parameters based on the first and second endpoints. The line parameters are then stored in a memory. A "calculate-only" control signals determines whether a line is drawn immediately after calculation (and storing) of the end parameters or whether the line is drawn responsive to a subsequent "start" signal. If the line is to be drawn responsive to the start signal, the line parameters may be modified prior to drawing the line.
摘要翻译： 线绘制电路接收定义线的第一和第二端点的参数，并基于第一和第二端点计算线路参数。 然后将线路参数存储在存储器中。 “仅计算”控制信号确定在计算（并存储）结束参数之后立即绘制线，还是响应于随后的“开始”信号绘制线。 如果要响应于起始信号来绘制线，则可以在绘制线之前修改线参数。
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公开(公告)号：US4633243A
公开(公告)日：1986-12-30
申请号：US592675
申请日：1984-03-23
摘要： In a method of storing characters in a display system having a display device with an orthogonal matrix of addressable points, each character is represented as a succession of strokes each constrained to lie in one of the eight fundamental directions of the matrix and, except for the first stroke, each starting at the end of the previous stroke. Each such stroke is stored in a binary coded form which includes a first binary number (direction code) defining the angular direction of the stroke, a second binary number (length code) defining a number of matrix steps from one addressable point to the next along the stroke in that direction, and a third binary number (move/draw code) defining the visibility of the stroke. In order to facilitate character rotation by any multiple of 45.degree. the direction code defining each fundamental direction corresponds to the addition modulo 2.sup.n of a binary constant to the direction code which defines the fundamental direction of 45.degree. thereto in a given direction of rotation, where n is the number of bits in the direction code.
摘要翻译： 在具有具有可寻址点的正交矩阵的显示装置的显示系统中存储字符的方法中，每个字符被表示为一系列笔划，每个笔划被限制在矩阵的八个基本方向之一中，除了 第一次中风，每个起始于上一次中风结束。 每个这样的笔划被存储为二进制编码形式，其包括限定笔划的角度方向的第一二进制数（方向代码），定义从一个可寻址点到下一个的多个矩阵步骤的第二二进制数（长度码） 在该方向上的笔画，以及定义笔画的可视性的第三个二进制数（移动/绘制代码）。 为了方便字符旋转45度的任何倍数，定义每个基本方向的方向代码对应于在给定的旋转方向上限定45°的基本方向的方向代码的二进制常数的加法模2n，其中 n是方向代码的位数。
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公开(公告)号：US4623880A
公开(公告)日：1986-11-18
申请号：US566245
申请日：1983-12-28
摘要： The invention concerns a graphics display system of the kind having a refresh raster display device, a line clipping mechanism for clipping line primitives for viewing in a selected rectangular viewport having horizontal and vertical edges parallel to the X and Y axes respectively of the display area of the display device, and a vector-to-raster converter for converting the clipped lines to patterns of discrete pels in a refresh buffer, the vector-to-raster converter including an incremental line drawing mechanism responsive to line information supplied by the clipping mechanism to draw the line starting at one endpoint and proceeding towards the other. In such a system, for at least some lines of a kind which have a first endpoint in the viewport and the second endpoint outside the viewport, the clipping mechanism is arranged to avoid calculating the intersection point of the line with the viewport edge intersected by the line, and the vector-to-raster converter is arranged to start the line drawing mechanism at the first endpoint and halt the line drawing mechanism when the currently generated coordinate along the display axis normal th the said viewport edge equals the coordinate of the viewport edge along the same axis.
摘要翻译： 本发明涉及一种具有刷新光栅显示装置的图形显示系统，用于剪切用于在所选矩形视口中观看的线基元的线剪切机构，所述矩形视口具有平行于X和Y轴的显示区域的X和Y轴的水平和垂直边 所述显示装置和用于将所述经剪切的线转换为刷新缓冲器中的离散像素的图案的矢量到光栅转换器，所述矢量到光栅转换器包括响应于由所述剪切机构提供的线信息的增量线绘制机构， 从一个终点开始绘制线，并向另一个终点前进。 在这种系统中，对于在视口中具有第一端点和视口外的第二端点的类型的至少一些线，该夹持机构被布置成避免计算该线与与该视口相交的视口边缘的交点 并且矢量到光栅转换器被布置为在第一端点处启动线条绘制机构，并且当沿着显示轴的当前生成的坐标垂直于所述视口边缘等于视口边缘的坐标时，停止线描绘机构 沿同一轴线。
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公开(公告)号：US6037951A
公开(公告)日：2000-03-14
申请号：US819399
申请日：1997-03-03
申请人： Thomas Michael Albers , John Vernon Eberst , Darwin Fontenot , Richard Lynn Pyra , Mark William Welker , Paul Berton Wood , Jack E. Bresenham
发明人： Thomas Michael Albers , John Vernon Eberst , Darwin Fontenot , Richard Lynn Pyra , Mark William Welker , Paul Berton Wood , Jack E. Bresenham
CPC分类号： G06T11/203
摘要： A graphics device includes first and second endpoint memories where coordinates of a line can be stored. State logic within the graphics device calculates line parameters from the first and second endpoints. The calculated line parameters include a line error term which can be stored in an error term memory. The error term memory is writeable from a source external to the graphics device, such as the CPU of a computer system, so that the external source can modify the contents of the error term register.
摘要翻译： 图形装置包括可存储线的坐标的第一和第二端点存储器。 图形设备内的状态逻辑从第一和第二端点计算线路参数。 计算的线参数包括可以存储在错误项存储器中的线误差项。 错误项存储器可以从外部的源写入到诸如计算机系统的CPU的图形设备，使得外部源可以修改错误项寄存器的内容。
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公开(公告)号：US5613053A
公开(公告)日：1997-03-18
申请号：US823529
申请日：1992-01-21
申请人： Thomas M. Albers , John V. Eberst , Darwin Fontenot , Richard L. Pyra , Mark W. Welker , Paul B. Wood , Jack E. Bresenham
发明人： Thomas M. Albers , John V. Eberst , Darwin Fontenot , Richard L. Pyra , Mark W. Welker , Paul B. Wood , Jack E. Bresenham
CPC分类号： G06T11/203
摘要： A graphics processor uses a line draw facility to receive first and second values indicative of the coordinates of respective first and second end points of a line. The reception of the second value is sensed by the line draw facility and line data is generated responsive to the sensing of the second value.
摘要翻译： 图形处理器使用线绘制工具来接收指示线的相应第一和第二端点的坐标的第一和第二值。 第二值的接收由线条绘制设备感测，并且响应于对第二值的感测产生线数据。
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公开(公告)号：US4996653A
公开(公告)日：1991-02-26
申请号：US138241
申请日：1987-12-28
摘要： In a line generator and a method for determining the individual pixels to be plotted for a line to be drawn in a display system, coded representations of a plurality of lines are stored in a line definition table. The coded representation of each individual line is a string of data items representing the transitions between adjacent pixels to be plotted for drawing the individual line. Preferably, only coded representations of lines up to a predetermined size (i.e. the length of the line in the case of a straight line) are stored in the line definition table. Strings of data items for representing the pixels to be plotted for longer lines to be drawn are still calculated as in the prior art. In this case, control logic determines whether there are coded representations of a line to be drawn in the line definition table, or not, and passes control to appropriate processing logic for determining the pixels to be plotted. In a preferred embodiment, the string of data items forming the coded representation of a line to be drawn is a string of binary digits and the value of each bit in the string represents a transition in one of two directions. This provides a very compact representation of the line.
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