graphics.c

c语言开发方面的经典问题,包括源代码.c语言开发所要注意的问题,以及在嵌入式等各方面的应用

/*
 * File: graphics.c
 * Version: 3.0
 * Last modified on Wed Sep 21 23:53:53 1994 by eroberts
 * -----------------------------------------------------
 * This file implements the graphics.h and extgraph.h interfaces
 * for the Borland/Windows platform.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <conio.h>
#include <windows.h>
#include <time.h>

#include "genlib.h"
#include "gcalloc.h"
#include "strlib.h"
#include "extgraph.h"

/*
 * Parameters
 * ----------
 * DesiredWidth    -- Desired width of the graphics window
 * DesiredHeight   -- Desired height of the graphics window
 * DefaultSize     -- Default point size
 * MaxTitle        -- Maximum window title length
 * MaxFontName     -- Maximum font name length
 * MaxFonts        -- Maximum number of fonts
 * LeftMargin      -- Margin from left of screen to both windows
 * RightMargin     -- Minimum margin to right of windows
 * TopMargin       -- Margin from top of screen to graphics window
 * BottomMargin    -- Minimum margin from bottom of screen to console window
 * WindowSep       -- Separation between graphics and console windows
 * ConsoleHeight   -- Height of the console window (pixels)
 * MinConsoleScale -- Smallest acceptable scale factor for the console
 * PStartSize      -- Starting size for polygon (must be greater than 1)
 * MaxColors       -- Maximum number of color names allowed
 * MinColors       -- Minimum number of colors the device must support
 * GWClassName     -- Class name of the graphics window
 * DefaultFont     -- Font that serves as the "Default" font
 */

#define DesiredWidth       7.0
#define DesiredHeight      4.0
#define DefaultSize       12
#define MaxTitle          75
#define MaxFontName       50
#define MaxFonts         100
#define LeftMargin        10
#define RightMargin       25
#define TopMargin          2
#define BottomMargin      30
#define WindowSep          5
#define ConsoleHeight    110
#define MinConsoleScale    0.8
#define PStartSize        50
#define MaxColors        256
#define MinColors         16

#define GWClassName "Graphics Window"
#define DefaultFont "System"

/*
 * Other constants
 * ---------------
 * LargeInt  -- Integer too large for a coordinate value
 * Epsilon   -- Small arithmetic offset to reduce aliasing/banding
 * Pi        -- Mathematical constant pi
 * AnyButton -- Union of all mouse buttons
 */

#define LargeInt 16000
#define Epsilon  0.00000000001
#define Pi       3.1415926535

#define AnyButton (MK_LBUTTON | MK_RBUTTON | MK_MBUTTON)

/*
 * Type: graphicsStateT
 * --------------------
 * This structure holds the variables that make up the graphics state.
 */

typedef struct graphicsStateT {
    double cx, cy;
    string font;
    int size;
    int style;
    bool erase;
    int color;
    struct graphicsStateT *link;
} *graphicsStateT;

/*
 * Type: fontEntryT
 * ----------------
 * This structure holds the data for a font.
 */

typedef struct {
    string name;
    int size, style;
    int points, ascent, descent, height;
    HFONT font;
} fontEntryT;

/*
 * Type: regionStateT
 * ------------------
 * The region assembly process has the character of a finite state
 * machine with the following four states:
 *
 *   NoRegion       Region has not yet been started
 *   RegionStarting Region is started but no line segments yet
 *   RegionActive   First line segment appears
 *   PenHasMoved    Pen has moved during definition
 *
 * The current state determines whether other operations are legal
 * at that point.
 */

typedef enum {
    NoRegion, RegionStarting, RegionActive, PenHasMoved
} regionStateT;

/*
 * Type: colorEntryT
 * -----------------
 * This type is used for the entries in the color table.
 */

typedef struct {
    string name;
    double red, green, blue;
} colorEntryT;

/*
 * Static table: fillList
 * ----------------------
 * This table contains the bitmap patterns for the various density
 * values.  Adding more patterns to this list increases the
 * precision with which the client can control fill patterns.
 * Note that this bitmap is inverted from that used on most
 * systems, with 0 indicating foreground and 1 indicating background.
 */

static short fillList[][8] = {
    { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF },
    { 0x77, 0xDD, 0x77, 0xDD, 0x77, 0xDD, 0x77, 0xDD },
    { 0x55, 0xAA, 0x55, 0xAA, 0x55, 0xAA, 0x55, 0xAA },
    { 0x88, 0x22, 0x88, 0x22, 0x88, 0x22, 0x88, 0x22 },
    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
};

#define NFills (sizeof fillList / sizeof fillList[0])

/*
 * Global variables
 * ----------------
 * initialized    -- TRUE if initialization has been done
 * pauseOnExit    -- TRUE if library should pause when exiting
 * consoleWindow  -- Window handle for console window
 * graphicsWindow -- Window handoe for graphics window
 * gdc            -- Graphics DC (screen)
 * osdc           -- Offscreen DC (memory backup)
 * osbits         -- Offscreen bitmap
 * drawPen        -- Pen used for drawing
 * erasePen       -- Pen used for erasing
 * nullPen        -- Pen used for filling
 * drawColor      -- Color used for drawing
 * eraseColor     -- Color used for erasing
 * windowTitle    -- Current window title (initialized statically)
 * xResolution    -- Horizontal resolution of screen (dots per inch)
 * yResolution    -- Vertical resolution of screen (dots per inch)
 * windowWidth    -- Width of graphics window (inches)
 * windowHeight   -- Height of graphics window (inches)
 * pixelWidth     -- Width of graphics window (pixels)
 * pixelHeight    -- Height of graphics window (pixels)
 * fontTable      -- Table of stored fonts
 * nFonts         -- Number of fonts in fontTable
 * currentFont    -- Index of current font in fontTable
 * regionState    -- Current state of the region
 * regionDensity  -- Fill density to apply to region
 * polygonPoints  -- Array of points used in current region
 * nPolygonPoints -- Number of active points
 * polygonSize    -- Number of allocated points
 * polygonBounds  -- Bounding box of polygon
 * colorTable     -- Table of defined colors
 * nColors        -- Number of defined colors
 * previousColor  -- Last color index set
 * stateStack     -- Stack of graphicStateT blocks
 * cx, cy         -- Current coordinates     | These
 * eraseMode      -- Setting of erase flag   | variables
 * textFont       -- Current font            | consititute
 * textStyle      -- Current style           | the current
 * pointSize      -- Current point size      | graphics
 * penColor       -- Color of pen            | state
 */

static bool initialized = FALSE;
static bool pauseOnExit = TRUE;

static HWND consoleWindow, graphicsWindow;
static HDC gdc, osdc;
static HBITMAP osBits;
static HPEN drawPen, erasePen, nullPen;
static COLORREF drawColor, eraseColor;
static PAINTSTRUCT ps;
static string windowTitle = "Graphics Window";

static double xResolution, yResolution;
static double windowWidth = DesiredWidth;
static double windowHeight = DesiredHeight;
static int pixelWidth, pixelHeight;

static fontEntryT fontTable[MaxFonts];
static int nFonts;
static int currentFont;

static regionStateT regionState;
static double regionDensity;
static POINT *polygonPoints;
static int nPolygonPoints;
static int polygonSize;
static RECT polygonBounds;
static HBITMAP fillBitmaps[NFills];

static colorEntryT colorTable[MaxColors];
static int nColors;
static int previousColor;

static graphicsStateT stateStack;

static double cx, cy;
static bool eraseMode;
static string textFont;
static int textStyle;
static int pointSize;
static int penColor;

static int mouseX, mouseY;
static bool mouseButton = FALSE;

/* Private function prototypes */

static void InitCheck(void);
static void InitGraphicsState(void);
static void InitDisplay(void);
static void InitDrawingTools(void);
static void DisplayExit(void);
static HWND FindConsoleWindow(void);
static BOOL CALLBACK EnumerateProc(HWND window, LPARAM clientData);
static void RegisterWindowClass(void);
static LONG FAR PASCAL GraphicsEventProc(HWND w, UINT msg,
                                         WPARAM p1, LPARAM p2);
static void DoUpdate(void);
static void DisplayClear(void);
static void PrepareToDraw(void);
static void DisplayLine(double x, double y, double dx, double dy);
static void DisplayArc(double xc, double yc, double rx, double ry,
                       double start, double sweep);
static void RenderArc(double x, double y, double rx, double ry,
                      double start, double sweep);
static void DisplayText(double x, double y, string text);
static void DisplayFont(string font, int size, int style);
static int FindExistingFont(string name, int size, int style);
static void SetLineBB(RECT *rp, double x, double y, double dx, double dy);
static void SetArcBB(RECT *rp, double xc, double yc,
                     double rx, double ry, double start, double sweep);
static void SetTextBB(RECT *rp, double x, double y, string text);
static void StartPolygon(void);
static void AddSegment(int x0, int y0, int x1, int y1);
static void DisplayPolygon(void);
static void AddPolygonPoint(int x, int y);
static void InitColors(void);
static int FindColorName(string name);

static bool StringMatch(string s1, string s2);
static bool PrefixMatch(string prefix, string str);
static int RectWidth(RECT *rp);
static int RectHeight(RECT *rp);
static void SetRectFromSize(RECT *rp, int x, int y, int width, int height);
static double Radians(double degrees);
static int Round(double x);
static double InchesX(int x);
static double InchesY(int y);
static int PixelsX(double x);
static int PixelsY(double y);
static int ScaleX(double x);
static int ScaleY(double y);
static int Min(int x, int y);
static int Max(int x, int y);

/* Exported entries */

/* Section 1 -- Basic functions from graphics.h */

void InitGraphics(void)
{
    if (!initialized) {
        initialized = TRUE;
        ProtectVariable(stateStack);
        ProtectVariable(windowTitle);
        ProtectVariable(textFont);
        InitColors();
        InitDisplay();
    }
    DisplayClear();
    InitGraphicsState();
}

void MovePen(double x, double y)
{
    InitCheck();
    if (regionState == RegionActive) regionState = PenHasMoved;
    cx = x;
    cy = y;
}

void DrawLine(double dx, double dy)
{
    InitCheck();
    switch (regionState) {
      case NoRegion:
        DisplayLine(cx, cy, dx, dy);
        break;
      case RegionStarting: case RegionActive:
        DisplayLine(cx, cy, dx, dy);
        regionState = RegionActive;
        break;
      case PenHasMoved:
        Error("Region segments must be contiguous");
    }
    cx += dx;
    cy += dy;
}

void DrawArc(double r, double start, double sweep)
{
    DrawEllipticalArc(r, r, start, sweep);
}

double GetWindowWidth(void)
{
    InitCheck();
    return (windowWidth);
}

double GetWindowHeight(void)
{
    InitCheck();
    return (windowHeight);
}

double GetCurrentX(void)
{
    InitCheck();
    return (cx);
}

double GetCurrentY(void)
{
    InitCheck();
    return (cy);
}

/* Section 2 -- Elliptical arcs */

void DrawEllipticalArc(double rx, double ry,
                       double start, double sweep)
{
    double x, y;

    InitCheck();
    x = cx + rx * cos(Radians(start + 180));
    y = cy + ry * sin(Radians(start + 180));
    switch (regionState) {
      case NoRegion:
        DisplayArc(x, y, rx, ry, start, sweep);
        break;
      case RegionStarting: case RegionActive:
        RenderArc(x, y, rx, ry, start, sweep);
        regionState = RegionActive;
        break;
      case PenHasMoved:
        Error("Region segments must be contiguous");
    }
    cx = x + rx * cos(Radians(start + sweep));
    cy = y + ry * sin(Radians(start + sweep));
}

/* Section 3 -- Graphical structures */

void StartFilledRegion(double grayScale)
{
    InitCheck();
    if (regionState != NoRegion) {
        Error("Region is already in progress");
    }
    if (grayScale < 0 || grayScale > 1) {
        Error("Gray scale for regions must be between 0 and 1");
    }
    regionState = RegionStarting;
    regionDensity = grayScale;
    StartPolygon();
}

void EndFilledRegion(void)
{
    InitCheck();
    if (regionState == NoRegion) {
        Error("EndFilledRegion without StartFilledRegion");
    }
    DisplayPolygon();
    regionState = NoRegion;
}

/* Section 4 -- String functions */

void DrawTextString(string text)
{
    InitCheck();
    if (regionState != NoRegion) {
        Error("Text strings are illegal inside a region");
    }
    DisplayText(cx, cy, text);
    cx += TextStringWidth(text);