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Annotation of Examples/AppKit/Draw/Line.m, revision 1.1

1.1     ! root        1: #import "draw.h"
        !             2: 
        !             3: @implementation Line : Graphic
        !             4: /*
        !             5:  * Drawing a line is simple except that we have to keep track of whether
        !             6:  * the line goes from the upper left to the lower right of the bounds or
        !             7:  * from the lower left to the upper right.  This can easily be determined
        !             8:  * every time a corner is moved to a different corner.  Therefore, all
        !             9:  * that is needed is to override moveCorner:to:constrain: to keep track
        !            10:  * of that.  It is an efficiency hack to have the downhill flag kept
        !            11:  * in our superclass's flags.
        !            12:  *
        !            13:  * This line is just a stub to get genstrings to generate
        !            14:  * a .strings file entry for the name of this type of Graphic.
        !            15:  * The name is used in the Undo New <Whatever> menu item.
        !            16:  *
        !            17:  * NXLocalString("Line", NULL, "Name of the tool that draws lines, i.e., the %s of the New %s operation.")
        !            18:  */
        !            19: 
        !            20: #define HIT_TOLERANCE 6.0
        !            21: 
        !            22: + initialize
        !            23: {
        !            24:     [Line setVersion:1];
        !            25:     return self;
        !            26: }
        !            27: 
        !            28: - init
        !            29: {
        !            30:     [super init];
        !            31:     startCorner = LOWER_LEFT;
        !            32:     return self;
        !            33: }
        !            34: 
        !            35: - (BOOL)isValid
        !            36: /*
        !            37:  * A line is validly created if EITHER of the dimensions is big enough.
        !            38:  */
        !            39: {
        !            40:     return(bounds.size.width >= 5.0 || bounds.size.height >= 5.0);
        !            41: }
        !            42: 
        !            43: static int oppositeCorner(int corner)
        !            44: {
        !            45:     switch (corner) {
        !            46:        case UPPER_RIGHT: return LOWER_LEFT;
        !            47:        case LOWER_LEFT: return UPPER_RIGHT;
        !            48:        case UPPER_LEFT: return LOWER_RIGHT;
        !            49:        case LOWER_RIGHT: return UPPER_LEFT;
        !            50:     }
        !            51: 
        !            52:     return corner;
        !            53: }
        !            54: 
        !            55: - (int)moveCorner:(int)corner to:(const NXPoint *)point constrain:(BOOL)flag
        !            56: /*
        !            57:  * Moves the corner to the specified point keeping track of whether the
        !            58:  * line is going uphill or downhill and where the start corner has moved to.
        !            59:  */
        !            60: {
        !            61:     int newcorner;
        !            62: 
        !            63:     newcorner = [super moveCorner:corner to:point constrain:flag];
        !            64: 
        !            65:     if (newcorner != corner) {
        !            66:        if ((newcorner == UPPER_RIGHT && corner == LOWER_LEFT) ||
        !            67:            (newcorner == UPPER_LEFT && corner == LOWER_RIGHT) ||
        !            68:            (newcorner == LOWER_RIGHT && corner == UPPER_LEFT) ||
        !            69:            (newcorner == LOWER_LEFT && corner == UPPER_RIGHT)) {
        !            70:        } else {
        !            71:            gFlags.downhill = !gFlags.downhill;
        !            72:        }
        !            73:        if (startCorner == corner) {
        !            74:            startCorner = newcorner;
        !            75:        } else {
        !            76:            startCorner = oppositeCorner(newcorner);
        !            77:        }
        !            78:     }
        !            79: 
        !            80:     return newcorner;
        !            81: }
        !            82: 
        !            83: - constrainCorner:(int)corner toAspectRatio:(float)ratio
        !            84: /*
        !            85:  * Constrains the corner to the nearest 15 degree angle.  Ignores ratio.
        !            86:  */
        !            87: {
        !            88:     NXCoord width, height;
        !            89:     double angle, distance;
        !            90: 
        !            91:     distance = hypot(bounds.size.width, bounds.size.height);
        !            92:     angle = atan2(bounds.size.height, bounds.size.width);
        !            93:     angle = (angle / 3.1415) * 180.0;
        !            94:     angle = floor(angle / 15.0 + 0.5) * 15.0;
        !            95:     angle = (angle / 180.0) * 3.1415;
        !            96:     width = floor(cos(angle) * distance + 0.5);
        !            97:     height = floor(sin(angle) * distance + 0.5);
        !            98: 
        !            99:     switch (corner) {
        !           100:        case LOWER_LEFT:
        !           101:            bounds.origin.x -= width - bounds.size.width;
        !           102:            bounds.origin.y -= height - bounds.size.height;
        !           103:            break;
        !           104:        case UPPER_LEFT:
        !           105:            bounds.origin.x -= width - bounds.size.width;
        !           106:            break;
        !           107:        case LOWER_RIGHT:
        !           108:            bounds.origin.y -= height - bounds.size.height;
        !           109:            break;
        !           110:     }
        !           111: 
        !           112:     bounds.size.width = width;
        !           113:     bounds.size.height = height;
        !           114: 
        !           115:     return self;
        !           116: }
        !           117: 
        !           118: - (int)cornerMask
        !           119: /*
        !           120:  * Only put corner knobs at the start and end of the line.
        !           121:  */
        !           122: {
        !           123:     if (gFlags.downhill) {
        !           124:        return(UPPER_LEFT_MASK|LOWER_RIGHT_MASK);
        !           125:     } else {
        !           126:        return(LOWER_LEFT_MASK|UPPER_RIGHT_MASK);
        !           127:     }
        !           128: }
        !           129: 
        !           130: - draw
        !           131: /*
        !           132:  * Calls drawLine to draw the line, then draws the arrows if any.
        !           133:  */
        !           134: {
        !           135:     if (bounds.size.width < 1.0 && bounds.size.height < 1.0) return self;
        !           136: 
        !           137:     [self setLineColor];
        !           138:     [self drawLine];
        !           139: 
        !           140:     if (gFlags.arrow) {
        !           141:        if (gFlags.downhill) {
        !           142:            if (((gFlags.arrow != ARROW_AT_START) &&
        !           143:                 (startCorner == LOWER_RIGHT)) ||
        !           144:                ((gFlags.arrow != ARROW_AT_END) &&
        !           145:                 (startCorner == UPPER_LEFT))) {
        !           146:                PSArrow(bounds.origin.x,
        !           147:                        bounds.origin.y + bounds.size.height,
        !           148:                        [self arrowAngle:UPPER_LEFT]);      
        !           149:            }
        !           150:            if (((gFlags.arrow != ARROW_AT_START) &&
        !           151:                 (startCorner == UPPER_LEFT)) ||
        !           152:                ((gFlags.arrow != ARROW_AT_END) &&
        !           153:                 (startCorner == LOWER_RIGHT))) {
        !           154:                PSArrow(bounds.origin.x + bounds.size.width,
        !           155:                        bounds.origin.y,
        !           156:                        [self arrowAngle:LOWER_RIGHT]);     
        !           157:            }
        !           158:        } else {
        !           159:            if (((gFlags.arrow != ARROW_AT_START) &&
        !           160:                 (startCorner == LOWER_LEFT)) ||
        !           161:                ((gFlags.arrow != ARROW_AT_END) &&
        !           162:                 (startCorner == UPPER_RIGHT))) {
        !           163:                PSArrow(bounds.origin.x + bounds.size.width,
        !           164:                        bounds.origin.y + bounds.size.height,
        !           165:                        [self arrowAngle:UPPER_RIGHT]);     
        !           166:            }
        !           167:            if (((gFlags.arrow != ARROW_AT_START) &&
        !           168:                 (startCorner == UPPER_RIGHT)) ||
        !           169:                ((gFlags.arrow != ARROW_AT_END) &&
        !           170:                 (startCorner == LOWER_LEFT))) {
        !           171:                PSArrow(bounds.origin.x,
        !           172:                        bounds.origin.y,
        !           173:                        [self arrowAngle:LOWER_LEFT]);      
        !           174:            }
        !           175:        }
        !           176:     }
        !           177: 
        !           178:     return self;
        !           179: }
        !           180: 
        !           181: - (BOOL)hit:(const NXPoint *)point
        !           182: /*
        !           183:  * Gets a hit if the point is within HIT_TOLERANCE of the line.
        !           184:  */
        !           185: {
        !           186:     NXRect r;
        !           187:     NXPoint p;
        !           188:     float lineangle, pointangle, distance;
        !           189:     float tolerance = HIT_TOLERANCE + linewidth;
        !           190: 
        !           191:     if (gFlags.locked || !gFlags.active) return NO;
        !           192: 
        !           193:     r = bounds;
        !           194:     if (r.size.width < tolerance) {
        !           195:        r.size.width += tolerance * 2.0;
        !           196:        r.origin.x -= tolerance;
        !           197:     }
        !           198:     if (r.size.height < tolerance) {
        !           199:        r.size.height += tolerance * 2.0;
        !           200:        r.origin.y -= tolerance;
        !           201:     }
        !           202: 
        !           203:     if (!NXMouseInRect(point, &r, NO)) return NO;
        !           204: 
        !           205:     p.x = point->x - bounds.origin.x;
        !           206:     p.y = point->y - bounds.origin.y;
        !           207:     if (gFlags.downhill) p.y = bounds.size.height - p.y;
        !           208:     if (p.x && bounds.size.width) {
        !           209:        lineangle = atan(bounds.size.height/bounds.size.width);
        !           210:        pointangle = atan(p.y/p.x);
        !           211:        distance = sqrt(p.x*p.x+p.y*p.y)*sin(fabs(lineangle-pointangle));
        !           212:     } else {
        !           213:        distance = fabs(point->x - bounds.origin.x);
        !           214:     }
        !           215: 
        !           216:     return((distance - tolerance) <= linewidth);
        !           217: }
        !           218: 
        !           219: /* Methods intended to be subclassed */
        !           220: 
        !           221: - (float)arrowAngle:(int)corner
        !           222: /*
        !           223:  * Returns the angle which the arrow should be drawn at.
        !           224:  */
        !           225: {
        !           226:     float angle;
        !           227:     angle = atan2(bounds.size.height, bounds.size.width);
        !           228:     angle = (angle / 3.1415) * 180.0;
        !           229:     switch (corner) {
        !           230:        case UPPER_RIGHT: return angle;
        !           231:        case LOWER_LEFT: return angle + 180.0;
        !           232:        case UPPER_LEFT: return 180.0 - angle;
        !           233:        case LOWER_RIGHT: return - angle;
        !           234:     }
        !           235:     return angle;
        !           236: }
        !           237: 
        !           238: - drawLine
        !           239: /*
        !           240:  * The actual line drawing is done here so that it can be subclassed.
        !           241:  */
        !           242: {
        !           243:     if (gFlags.downhill) {
        !           244:        PSLine(bounds.origin.x, bounds.origin.y + bounds.size.height,
        !           245:               bounds.size.width, - bounds.size.height);
        !           246:     } else {
        !           247:        PSLine(bounds.origin.x, bounds.origin.y,
        !           248:               bounds.size.width, bounds.size.height);
        !           249:     }
        !           250:     return self;
        !           251: }
        !           252: 
        !           253: /* Archiving methods */
        !           254: 
        !           255: - write:(NXTypedStream *)stream
        !           256: {
        !           257:     [super write:stream];
        !           258:     NXWriteType(stream, "i", &startCorner);
        !           259:     return self;
        !           260: }
        !           261: 
        !           262: - read:(NXTypedStream *)stream
        !           263: {
        !           264:     [super read:stream];
        !           265:     if (NXTypedStreamClassVersion(stream, "Line") > 0) {
        !           266:        NXReadType(stream, "i", &startCorner);
        !           267:     } else {
        !           268:        startCorner = LOWER_LEFT;
        !           269:     }
        !           270:     return self;
        !           271: }
        !           272: 
        !           273: @end

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