Developer CD Series 2000 June: Reference Library/Dev.CD Jun 00 RL Disk 1.toast/pc/technical documentation/develop/develop issue 28/develop issue 28 code/sketch/source/adts/elementhelpers.c

C/C++ Source or Header | 1996-08-24 | 17.0 KB | 678 lines

/****************************************************************************
 *
 * ElementHelpers.c
 *
 * functions related to elements
 *
 ****************************************************************************/
#include <string.h>

#include "ElementHelpers.h"

#include "Assertion.h"
#include "DocumentADT.h"
#include "ElementADT.h"
#include "Structs.h"
#include "StringUtils.h"

static Rect     CalculateGroupBounds            (ElementReference element);
static Rect     CalculatePolygonBounds        (ElementReference element);

/*****************************************************************************
 *
 * GetFirstSubElement
 *
 * Retrieves the first element in an element’s sub-element list
 * (skips the list header node). If the sub-element list is empty, NIL is
 * returned.
 *
 *****************************************************************************/
ElementReference GetFirstSubElement(ElementReference element)
{
    ElementList            sublist;
    ElementReference    firstsub;

    firstsub = nil;

    sublist = GetElementSubElementList(element);
    if (sublist != nil)
        firstsub = GetFirstElement(sublist);

    return firstsub;
}



/*****************************************************************************
 *
 * GetElementByNumber
 *
 * Recursively searches an element list looking for a specific element by an
 * element number.
 * The element number is a unique number: no two elements in any list
 * in any document will have the same element number.
 *
 *****************************************************************************/
ElementReference GetElementByNumber(ElementList list, unsigned long number)
{
    ElementReference    iterator;
    ElementReference    element;

    element = nil;

    for (iterator = GetFirstElement(list); (iterator != nil) && (element == nil); iterator = GetNextElement(iterator))
    {
        if (GetElementNumber(iterator) == number)
            element = iterator;

        if (element == nil)
            if (GetFirstSubElement(iterator) != nil)
                element = GetElementByNumber(GetSubElementList(iterator), number);
    }

    return element;
}


/*****************************************************************************
 *
 * GetGroupElementBelongsTo
 *
 * Returns the group that contains a specified element. If the element is at
 * the root of the document's element list nil will be returned.
 *
 *****************************************************************************/
ElementReference GetGroupElementBelongsTo(ElementList list, ElementReference element)
{
    ElementReference    groupElement        = nil;

    if (IsElementInList(list, element, &groupElement))                                                // this will recursively search the list and group elements.
    {
        if (groupElement == element)                                                                        // we found it at the root level, so return nil as advertised.  dsc
            groupElement = nil;
    }

    return groupElement;
}


/*****************************************************************************
 *
 * IsElementInList
 *
 *    This function recursively searches lists and Group elements for "element"
 *
 *    Returns :
 *
 *        true if found.
 *        groupElement is set to == element for the deepest level
 *        groupElement is set to the group owning the "element" for the next to deepest level
 *        groupElement passes on the result from there on.
 *
 *   NOTE:  If there is only 1 level, and "element" is found, then "element"
 *          is returned.  This is useful for GetGroupElementBelongsTo to then check it
 *          and return nil as advertised.dsc
 *
 *****************************************************************************/
Boolean IsElementInList(ElementList list, ElementReference element, ElementReference *groupElement)
{
    ElementType            elementType;
    ElementReference    tempElement;
    ElementReference    returnedElement    =    nil;
    Boolean                foundIt                = false;

    *groupElement        = nil;

    tempElement        = GetFirstElement(list);                                                                        // get first element in list

    if ((tempElement != nil) && (tempElement == element))                                                        // check the first element in the list.
    {
        *groupElement = tempElement;                                                                                    // this will flag the previous level to return that group as the result (or if at the root this will flag the root to then return nil).
        foundIt = true;
    }

    while ((tempElement != nil)  && (!foundIt))                                                                    // go until we the object or the end of the line
    {
        elementType = GetElementType(tempElement);

        if (elementType == kGroup)
        {
            if (IsElementInList(GetElementSubElementList(tempElement), element, &returnedElement))
            {
                foundIt = true;

                if (element == returnedElement)                                                                        // need to flag so I know that at this level, this is the group element to pass back!
                    *groupElement = tempElement;
                else
                    *groupElement = returnedElement;                                                                    // pass on through this element with no changes
            }
        }

        if (!foundIt)
        {
            tempElement = GetNextElement(tempElement);                                                            // move to the next element and try again

            if (tempElement == element)
            {
                *groupElement = tempElement;                                                                            // this will flag the previous level to return that group as the result (or if at the root this will flag the root to then return nil).
                foundIt = true;
            }
        }
    }

    return foundIt;
}

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

long
CountElementsByClass(ElementList list, DescType objectClass)
{
    OSErr                    error         = noErr;
    long                    numElements = 0L;

    ElementReference  element         = nil;
    ElementType       elementType;

    if (objectClass == typeWildCard || objectClass == cGraphicObject)
    {
        numElements = CountElements(list);
    }
    else
    {
        ElementType    requestedType;
        error = ConvertObjectClassToElementType(objectClass, &requestedType);

        element = GetFirstElement(list);
        while (element != nil)
        {
            elementType = GetElementType(element);
           if (requestedType == elementType)
           {
               numElements++;
           }
            element = GetNextElement(element);
        }
    }

    return numElements;
}


//----------------------------------------------------------------------------------
// Note: This does not return the element's unique element number, but instead
// it returns the index of that type of element: for instance
// it returns 4 when the element is the 4th rectangle in a document

long
GetIndexForElementType(DocumentReference document, ElementReference element, ElementType elementType)
{
    OSErr      error                         = noErr;
    Boolean foundIt               = false;

    ElementList         list;

    ElementReference  iter;
    ElementType            iterType;

    long                    index       = 0L;
    long              numElements = 0L;


    list = GetDocumentElementList(document);

    // First, how many elements of this type are there?

    iter = GetFirstElement(list);
    while (iter != nil)
    {
        iterType = GetElementType(iter);

       if (elementType == typeWildCard || elementType == cGraphicObject || elementType == iterType)
       {
           numElements++;
       }
        iter = GetNextElement(iter);
    }

    // Next, what is the index of the requested element and elementType or objectClass?

    iter = GetFirstElement(list);
    while (iter != nil)
    {
        iterType = GetElementType(iter);

       if (elementType == typeWildCard || elementType == cGraphicObject || elementType == iterType)
            index++;

        if (iter == element)
            break;

        iter = GetNextElement(iter);
    }

    if (iter != nil && iter == element)
    {
        index = numElements - index + 1;  // because element 1 is at the end of the list, not the beginning.
    }
    else
    {
        index = 0;    // This is an invalid number for an index, but technically -1, -2, etc. are valid
    }                    // because -1 means the last element, -2 means next-to-last, etc. in AppleScript

    return index;
}

//----------------------------------------------------------------------------------
// Note: This does not return the element's unique element number, but instead
// it returns the index of that type of element: for instance
// it returns 4 when the element is the 4th rectangle in a document

long
GetIndexForSubElementType(DocumentReference document, ElementReference element, ElementReference subElement, ElementType elementType)
{
    #pragma unused (document)

    OSErr      error                         = noErr;
    Boolean foundIt               = false;

    ElementList         list             = GetSubElementList(element);
    ElementReference  tempElement = nil;

    long                    index       = 0L;
    long              numElements = 0L;

    // First, how many elements of this type are there?

    tempElement = GetFirstElement(list);
    while (tempElement != nil)
    {
       if (elementType == typeWildCard || elementType == cGraphicObject || GetElementType(tempElement) == elementType)
       {
           numElements++;
       }
        tempElement = GetNextElement(tempElement);
    }

    // Next, what is the index of the requested element and elementType?

    tempElement = GetFirstElement(list);
    while (tempElement != nil)
    {
       if (elementType == typeWildCard || elementType == cGraphicObject || GetElementType(tempElement) == elementType)
            index++;

        if (tempElement == subElement)
            break;

        tempElement = GetNextElement(tempElement);
    }

    if (tempElement != nil && tempElement == subElement)
    {
        index = numElements - index + 1;  // because element 1 is at the end of the list, not the beginning.
    }
    else
    {
        index = 0;    // This is an invalid number for an index, but technically -1, -2, etc. are valid
    }                    // because -1 means the last element, -2 means next-to-last, etc. in AppleScript

    return index;
}

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

OSErr
FindElementByIndex(ElementList list, DescType objectClass, long index, ElementReference *element)
{
    OSErr    error                         = noErr;

    ElementReference  tempElement = nil;
    ElementType            elementType;
    ElementType            requestedType;

    long                    i            = 1L;
    long                    numElements = 0L;
    Boolean                foundIt      = false;

    *element = nil;

    if (objectClass == typeWildCard || objectClass == cGraphicObject)
    {
        numElements = CountElements(list);
    }
    else
    {
        numElements = CountElementsByClass(list, objectClass);
        error = ConvertObjectClassToElementType(objectClass, &requestedType);
    }

    // Negative indexes are offsets from the END of the element list:
    // rectangle -1 is the last rectangle, rectangle -2 is the next to last rectangle, etc.

    if (index < 0)
    {
        index = numElements + 1 + index;        // convert offset from end of list to offset from beginning of list
    }

    index = numElements - index + 1;  // because element 1 is at the end of the list, not the beginning.

    if (index < 1 || index > numElements)
        error = errAEIllegalIndex;

    // Find the element of the requested type with the requested index

    if (error == noErr)
    {
        i = 1L;
        tempElement = GetFirstElement(list);

        while (tempElement != nil)
        {
            elementType = GetElementType(tempElement);

           if (objectClass == typeWildCard || objectClass == cGraphicObject)
           {
               if (i == index)
               {
                   foundIt = true;
                   break;
               }
               i++;
           }
           else if (requestedType == elementType)
           {
               if (i == index)
               {
                   foundIt = true;
                   break;
               }
               i++;
           }
            tempElement = GetNextElement(tempElement);
        }
    }

    // return the element, if found

    if (error == noErr)
    {
        if (foundIt)
            *element = tempElement;
        else
            error = errAENoSuchObject;
    }

    return error;
}

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

ElementReference
FindElementByUniqueID(ElementList list, long uniqueID)
{
    ElementReference  element         = nil;
    Boolean                foundIt     = false;

    // Find the element of the requested ID

    element = GetFirstElement(list);

    while (element != nil)
    {
        if (GetElementNumber(element) == uniqueID)
        {
            foundIt = true;
            break;
        }
        element = GetNextElement(element);
    }

    if (foundIt == false)
        element = nil;

    return element;
}

//----------------------------------------------------------------------------------
// Convert AppleEvent class to elementType code

OSErr
ConvertObjectClassToElementType(const DescType objectClass, ElementType *elementType)
{
    OSErr    error = noErr;

    switch (objectClass)
    {
        case cOval:
            *elementType = kQDOval;
            break;

        case cPolygon:
            *elementType = kQDPolygon;
            break;

        case cRectangle:
            *elementType = kQDRect;
            break;

        case cRoundedRectangle:
            *elementType = kQDRoundRect;
            break;

        case cGraphicLine:
            *elementType = kQDLine;
            break;

        case cGraphicObject:
        case typeWildCard:
            *elementType = (ElementType) typeWildCard;
            break;

        case cGroupedGraphic:
            *elementType = kGroup;
            break;

        default:
            error = errAECantHandleClass;
            break;
    }

    return error;
}

//----------------------------------------------------------------------------------
// Convert an elementType code to AppleEvent class

OSErr
ConvertElementTypeToObjectClass(const ElementType elementType, DescType *objectClass)
{
    OSErr    error = noErr;

    switch (elementType)
    {
        case kQDOval:
            *objectClass = cOval;
            break;

        case kQDPolygon:
            *objectClass = cPolygon;
            break;

        case kQDRect:
            *objectClass = cRectangle;
            break;

        case kQDRoundRect:
            *objectClass = cRoundedRectangle;
            break;

        case kQDLine:
            *objectClass = cGraphicLine;
            break;

        case kGroup:
            *objectClass = cGroupedGraphic;
            break;

        case kUnknownElement:
        default:
            error = errAECantHandleClass;
            break;
    }

    return error;
}

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

void PopulateElementWithDefaultData(ElementReference element)
{
    RGBColor black        = {0x0000, 0x0000, 0x0000};
    RGBColor white     = {0xFFFF, 0xFFFF, 0xFFFF};
    Point        ovalSize = { 20,  20};
    Rect        bounds   = {  0,   0, 100,100};
    Point    p1            = {  0,   0};
    Point        p2       = {100, 100};

    SetElementBoundingBox(element, bounds);

    SetElementStrokePenHeight(element,     1);
    SetElementStrokePenWidth(element,     1);

    SetElementStrokeColor(element, black);
    SetElementFillColor(element, white);

    SetElementRoundRectOvalSize(element, ovalSize);
    SetElementLineBeginPoint(element, p1);
    SetElementLineEndPoint(element,   p2);

}

#pragma mark -
/*****************************************************************************
 *
 * CalculateElementBounds
 *
 * Public function to get the bounds of both simple and complex objects
 *
 *****************************************************************************/

Rect CalculateElementBounds(ElementReference element)
{
    Rect    objectBounds;
    Point p1;
    Point p2;

    switch (GetElementType(element))
    {
        case kQDPolygon:
                objectBounds = CalculatePolygonBounds(element);
                break;

        case kQDRect:
        case kQDRoundRect:
        case kQDOval:
                objectBounds = GetElementBoundingBox(element);
                break;

        case kQDLine:
                p1 = GetElementLineBeginPoint(element);
                p2 = GetElementLineEndPoint(element);

                objectBounds.top         = min(p1.v, p2.v);
                objectBounds.left     = min(p1.h, p2.h);
                objectBounds.bottom     = max(p1.v, p2.v);
                objectBounds.right     = max(p1.h, p2.h);
                break;

        case kGroup:
                objectBounds = CalculateGroupBounds(element);
                break;

        default:
                Assert(kAssertAlways, "Unknown object in CalculateElementBounds");
                break;
        }

    Assert(objectBounds.top  <= objectBounds.bottom, "IMAGING: CalculateElementBounds said that top is greater than bottom");
    Assert(objectBounds.left <= objectBounds.right,  "IMAGING: CalculateElementBounds said that left is greater than right");

    return objectBounds;
}

/*****************************************************************************
 *
 * CalculateGroupBounds
 *
 * walk the subElementList and Union all the visible elements bounding boxes together
 * groupBounds being passed to this function should be set to an empty rectangle
 *
 *****************************************************************************/

static Rect CalculateGroupBounds(ElementReference element)
{
    ElementReference    iterator;
    Rect                    groupBounds    = {0, 0, 0, 0};
    Rect                    objectBounds;
    ElementList            list;

    list = GetSubElementList(element);

    for (iterator = GetFirstElement(list); iterator != nil; iterator = GetNextElement(iterator))
    {
        if (GetElementType(iterator) == kGroup)
            objectBounds = CalculateGroupBounds(iterator);
        else
            objectBounds = CalculateElementBounds(iterator);

        if(EmptyRect(&groupBounds))
            groupBounds = objectBounds;
        else
            UnionRect(&groupBounds, &objectBounds, &groupBounds);
    }

    return groupBounds;
}

/*****************************************************************************
 *
 * CalculatePolygonBounds
 *
 * Polygons draw outside of their bounding box (go figure!) so we add the
 * pen size to the right and bottom side of the bounding box
 *
 *****************************************************************************/

static Rect CalculatePolygonBounds(ElementReference element)
{
    Rect            objectBounds = {0, 0, 0, 0};
    PolyHandle    polygon;
    short            strokeWidth;
    short            strokeHeight;

    polygon = GetElementPolygon(element);

    if (polygon != nil)
    {
        objectBounds = (**polygon).polyBBox;

        strokeWidth = GetElementStrokePenWidth(element);
        if(strokeWidth < 1)
            strokeWidth = 1;
        objectBounds.right  += strokeWidth;


        strokeHeight = GetElementStrokePenWidth(element);
        if(strokeHeight < 1)
            strokeHeight = 1;
        objectBounds.bottom += strokeHeight;
    }

    return objectBounds;
}