// ShowInitIcon - version 1.0.1, May 30th, 1995

// This code is intended to let INIT writers easily display an icon at startup time.

// View in Geneva 9pt, 4-space tabs

// Written by: Peter N Lewis <peter@mail.peter.com.au>, Jim Walker <JWWalker@aol.com>

// and Franois Pottier <pottier@dmi.ens.fr>, with thanks to previous ShowINIT authors.

// Send comments and bug reports to Franois Pottier.

// This version features:

// - Short and readable code.

// - Correctly wraps around when more than one row of icons has been displayed.

// - works with System 6

// - Built with Universal Headers & CodeWarrior. Should work with other headers/compilers.

#include <Memory.h>

#include <Resources.h>

#include <Icons.h>

#include <OSUtils.h>

#include "ShowInitIcon.h"

// You should set SystemSixOrLater in your headers to avoid including glue for SysEnvirons.

// ---------------------------------------------------------------------------------------------------------------------

// Set this flag to 1 if you want to compile this file into a stand-alone resource (see note below).

// Set it to 0 if you want to include this source file into your INIT project.

#if 0

#define ShowInitIcon main

#endif

// ---------------------------------------------------------------------------------------------------------------------

// The ShowINIT mechanism works by having each INIT read/write data from these globals.

// The MPW C compiler doesn't accept variables declared at an absolute address, so I use these macros instead.

// Only one macro is defined per variable; there is no need to define a Set and a Get accessor like in <LowMem.h>.

#define LMVCoord            (* (short*) 0x92A)

#define LMVCheckSum     (* (short*) 0x928)

#define LMHCoord            (* (short*) 0x92C)

#define LMHCheckSum     (* (short*) 0x92E)

// ---------------------------------------------------------------------------------------------------------------------

// Prototypes for the subroutines. The main routine comes first; this is necessary to make THINK C's "Custom Header" option work.

static unsigned short CheckSum (unsigned short x);

static void ComputeIconRect (Rect* iconRect, Rect* screenBounds);

static void AdvanceIconPosition (Rect* iconRect);

static void DrawBWIcon (short iconID, Rect *iconRect);

// ---------------------------------------------------------------------------------------------------------------------

// Main routine.

typedef struct {

    QDGlobals           qd;                                 // Storage for the QuickDraw globals

    long                qdGlobalsPtr;                           // A5 points to this place; it will contain a pointer to qd

} QDStorage;

pascal void ShowInitIcon (short iconFamilyID, Boolean advance)

{

    long                oldA5;                              // Original value of register A5

    QDStorage           qds;                                    // Fake QD globals

    CGrafPort           colorPort;

    GrafPort            bwPort;

    Rect                destRect;

    SysEnvRec       environment;                            // Machine configuration.

    oldA5 = SetA5((long) &qds.qdGlobalsPtr);                        // Tell A5 to point to the end of the fake QD Globals

    InitGraf(&qds.qd.thePort);                              // Initialize the fake QD Globals

    SysEnvirons(curSysEnvVers, &environment);                   // Find out what kind of machine this is

    ComputeIconRect(&destRect, &qds.qd.screenBits.bounds);          // Compute where the icon should be drawn

    if (environment.systemVersion >= 0x0700 && environment.hasColorQD) {

        OpenCPort(&colorPort);

        PlotIconID(&destRect, atNone, ttNone, iconFamilyID);

        CloseCPort(&colorPort);

    }

    else {

        OpenPort(&bwPort);

        DrawBWIcon(iconFamilyID, &destRect);

        ClosePort(&bwPort);

    }

    if (advance)

        AdvanceIconPosition (&destRect);

    SetA5(oldA5);                                           // Restore A5 to its previous value

}

// ---------------------------------------------------------------------------------------------------------------------

// A checksum is used to make sure that the data in there was left by another ShowINIT-aware INIT.

static unsigned short CheckSum (unsigned short x)

{

    return ((x << 1) | (x >> 15)) ^ 0x1021;

}

// ---------------------------------------------------------------------------------------------------------------------

// ComputeIconRect computes where the icon should be displayed.

static void ComputeIconRect (Rect* iconRect, Rect* screenBounds)

{

    if (CheckSum(LMHCoord) != LMHCheckSum)                  // If we are first, we need to initialize the shared data.

        LMHCoord = 8;

    if (CheckSum(LMVCoord) != LMVCheckSum)

        LMVCoord = screenBounds->bottom - 40;

    if (LMHCoord + 34 > screenBounds->right) {                  // Check whether we must wrap

        iconRect->left = 8;

        iconRect->top = LMVCoord - 40;

    }

    else {

        iconRect->left = LMHCoord;

        iconRect->top = LMVCoord;

    }

    iconRect->right = iconRect->left + 32;

    iconRect->bottom = iconRect->top + 32;

}

// AdvanceIconPosition updates the shared global variables so that the next extension will draw its icon beside ours.

static void AdvanceIconPosition (Rect* iconRect)

{

    LMHCoord = iconRect->left + 40;                         // Update the shared data

    LMVCoord = iconRect->top;

    LMHCheckSum = CheckSum(LMHCoord);

    LMVCheckSum = CheckSum(LMVCoord);

}

// DrawBWIcon draws the 'ICN#' member of the icon family. It works under System 6.

static void DrawBWIcon (short iconID, Rect *iconRect)

{

    Handle      icon;

    BitMap      source, destination;

    GrafPtr     port;

    icon = Get1Resource('ICN#', iconID);

    if (icon != NULL) {

        HLock(icon);

                                                        // Prepare the source and destination bitmaps.

        source.baseAddr = *icon + 128;                      // Mask address.

        source.rowBytes = 4;

        SetRect(&source.bounds, 0, 0, 32, 32);

        GetPort(&port);

        destination = port->portBits;

                                                        // Transfer the mask.

        CopyBits(&source, &destination, &source.bounds, iconRect, srcBic, nil);

                                                        // Then the icon.

        source.baseAddr = *icon;

        CopyBits(&source, &destination, &source.bounds, iconRect, srcOr, nil);

    }

}

// ---------------------------------------------------------------------------------------------------------------------

// Notes

// Checking for PlotIconID:

// We (PNL) now check for system 7 and colour QD, and use colour graf ports and PlotIconID only if both are true

// Otherwise we use B&W grafport and draw using PlotBWIcon.