第三章 基本觀念 電腦繪圖與動畫 (Computer Graphics & Animation) Object Data Image 第三章 基本觀念 電腦繪圖與動畫 (Computer Graphics & Animation) Object Data Image Scan Conversion 物體資料數據 影像

Object(物體) Data(數據) Graphics Command(指令) Graphics Application Program Display Processor 點、線、圓 曲線、面 特殊效果 Scan Conversion Frame Buffer （硬體及軟體） Display Controller （硬體） Monitor （螢幕）

Geometric Data Object Image 幾何資料 物件 影像 Computer Graphics Object Image Image Processing Pattern Recognition Creation 建構 Manipulation 操作 Display 顯示 Computer Graphics

CAD CAD/CAM 電腦輔助設計與製造 對象： 幾何 要求： 事實 目的： 設計、分析、應用 Computer Graphics 電腦繪圖 對象： 畫素 要求： 效果 目的： 表現、模擬、互動

Computer Graphics 電腦繪圖 何謂電腦繪圖？ What is Computer Graphics？ Communication between human beings and computers 用電腦化的方法來創造、操作及顯示影像 Defined as creation,manipulation and display of graphic images by computerized method Storing Viewing Modification Analysis Retrieving Include Creation Manipulation Display

Study scope 數據 Data Input Device 輸入裝置 ？ HOW 電腦繪圖方法 Computer Graphics 輸出裝置 Output Display Device 影像 Image

… Design Cycle Specification and Requirement Creation of Design Analysis and Evaluation Manufacturing and sales

CAD Computer-Aided Drafting Computer-Aided Drawing How to draw image Computer-Aided Design How to design How to represent a model How to use data for application Computer-Aided Design How to display data Image

…………… …………… Pixels Scan Conversion Frame Buffer Display Image Graphic entity Display processor Memory Display Controller Each Pixel In 2-D array memory …………… pixels ……………

CGA (Computer Graphics Adapter) EGA (Enhanced Graphics Adapter) VGA (Video Graphics Adapter) 640*480 SVGA (Super VGA) 800*600 XGA 1024*768

Pixel position definition Line Definition Vector Bitmap Raster 向量空間 影像空間 （x2,y2） Object Geometric Definition Object Space Vector Space （x1,y1） Computer Graphics Pixel position definition Image Pixel Definition Image Space Bitmap Space

Raster Display Raster-Scan Picture on screen as a set of Pixel points 畫素 Raster Display Screen Example： resolution 640*480（VGA） Scan Line pattern 1 2 3 4 5 Scan from： Left to Right Top to Bottom

Illuminating Pixels Scan Conversion Frame Buffer Display Image Display processor Memory Display controller 。Each pixel in 2-D array in memory Frame buffer bitmap 。512*512 display screen requires 262,144 pixel memory address 。1M 2M,……

. 0110000 1001110 0001100 Frame Buffer Display Image on Screen Each pixel is an （x,y）coordinate on Screen . y To display（x,y）pixel on screen x

Black and White 2 intensity level ON/OFF Single-bit-plane frame buffer Black and White with shades color Additional bit-planes 3 bit-plane 8 intensity level 0~7

Black and White TV 8 bit planes Intensity level明暗度 High quality color 24 bit planes Each with Primary colors（RGB） Red，Green，Blue colors VGA 640*400*8=256K 800*600*8=480K 256 colors 1024*768*8 通常 1M 1024*768 true 24 bit color 通常2M

3-bit，N bit 彩色

24-bit 彩色

電腦繪圖畫線 由點的轉換

Route through a Enu tree Typical screen layout