PEDisplayImpl.mesa
Written by Darlene Plebon on August 24, 1983 9:49 am
Path display routines.
DIRECTORY
Graphics USING [black, Color, Context, CurveTo, DrawStroke, DrawTo, LineTo, MoveTo, NewPath, Path, SetColor, SetCP, SetFat, white],
PEBezier USING [Bezier, SegmentToBezier],
PEDisplay,
PETypes,
PETrajectoryOps USING [ForAllVertices, IsAKnot, VertexProc],
PEViewer USING [DrawInViewer, DrawProc],
ViewerClasses USING [Viewer];
PEDisplayImpl: CEDAR PROGRAM
IMPORTS Graphics, PEBezier, PETrajectoryOps, PEViewer
EXPORTS PEDisplay =
BEGIN OPEN PEBezier, PEDisplay, PETrajectoryOps, PETypes, PEViewer;
white: Graphics.Color = Graphics.white;
black: Graphics.Color = Graphics.black;
grey: Graphics.Color = [r: 100, g: 100, b: 100];
DrawSegmentAndVertices: PUBLIC PROCEDURE [pathViewer: ViewerClasses.Viewer, segment: Segment, undo: BOOLEAN ← FALSE, background: BOOLEAN ← FALSE] = {
This routine draws the specified segment and its vertices. If undo is true, the drawing color is white (to erase), otherwise it is grey when background is true and black when background is false.
DrawVertices[pathViewer, segment, undo, background];
DrawSegment[pathViewer, segment, undo, background];
};
DrawVertices: PUBLIC PROCEDURE [pathViewer: ViewerClasses.Viewer, segment: Segment, undo: BOOLEAN ← FALSE, background: BOOLEAN ← FALSE] = {
This routine draws the vertices of the specified segment. If undo is true, the drawing color is white (to erase), otherwise it is grey when background is true and black when background is false.
DoDrawVertex: VertexProc = {
DrawVertex[pathViewer, v.first, undo, background];
};
ForAllVertices[segment.vertices, DoDrawVertex];
};
DrawControlPoints: PUBLIC PROCEDURE [pathViewer: ViewerClasses.Viewer, segment: Segment, undo: BOOLEAN ← FALSE, background: BOOLEAN ← FALSE] = {
This routine draws only the control point vertices of the specified segment. If undo is true, the drawing color is white (to erase), otherwise it is grey when background is true and black when background is false.
DoDrawControlPoint: VertexProc = {
IF ~IsAKnot[v] THEN DrawVertex[pathViewer, v.first, undo, background];
};
ForAllVertices[segment.vertices, DoDrawControlPoint];
};
DrawVertex: PUBLIC PROCEDURE [pathViewer: ViewerClasses.Viewer, vertex: Vertex, undo: BOOLEAN ← FALSE, background: BOOLEAN ← FALSE] = {
This routine draws only the specified vertex. If undo is true, the drawing color is white (to erase), otherwise it is grey when background is true and black when background is false.
DoDrawVertex: DrawProc = {
side: REAL = 2.0;
SELECT TRUE FROM
undo => Graphics.SetColor[context, white];
background => Graphics.SetColor[context, grey];
ENDCASE => Graphics.SetColor[context, black];
IF vertex.fixed THEN {     -- an X
Graphics.SetCP[context, vertex.point.x - side, vertex.point.y - side];
Graphics.DrawTo[context, vertex.point.x + side, vertex.point.y + side];
Graphics.SetCP[context, vertex.point.x + side, vertex.point.y - side];
Graphics.DrawTo[context, vertex.point.x - side, vertex.point.y + side];
}
ELSE {         -- a box
Graphics.SetCP[context, vertex.point.x - side, vertex.point.y - side];
Graphics.DrawTo[context, vertex.point.x + side, vertex.point.y - side];
Graphics.DrawTo[context, vertex.point.x + side, vertex.point.y + side];
Graphics.DrawTo[context, vertex.point.x - side, vertex.point.y + side];
Graphics.DrawTo[context, vertex.point.x - side, vertex.point.y - side];
};
};
DrawInViewer[pathViewer, DoDrawVertex];
};
DrawSegment: PUBLIC PROCEDURE [pathViewer: ViewerClasses.Viewer, segment: Segment, undo: BOOLEAN ← FALSE, background: BOOLEAN ← FALSE] = {
This routine draws only the specified segment but not its vertices. If undo is true, the drawing color is white (to erase), otherwise it is grey when background is true and black when background is false.
DoDrawSegment: DrawProc = {
path: Graphics.Path ← Graphics.NewPath[4];
bezier: Bezier;
SELECT TRUE FROM
segment.fp = NIL => {
Graphics.MoveTo[self: path, x: segment.vertices.first.point.x, y: segment.vertices.first.point.y];
Graphics.LineTo[self: path, x: segment.vertices.first.point.x, y: segment.vertices.first.point.y];
};
segment.vertices.rest = NIL => {
Graphics.MoveTo[self: path, x: segment.fp.point.x, y: segment.fp.point.y];
Graphics.LineTo[self: path, x: segment.vertices.first.point.x, y: segment.vertices.first.point.y];
};
ENDCASE => {
bezier ← SegmentToBezier[segment];
Graphics.MoveTo[self: path, x: bezier.b0.x, y: bezier.b0.y];
Graphics.CurveTo[self: path, x1: bezier.b1.x, y1: bezier.b1.y, x2: bezier.b2.x, y2: bezier.b2.y, x3: bezier.b3.x, y3: bezier.b3.y];
};
SELECT TRUE FROM
undo => Graphics.SetColor[context, white];
background => Graphics.SetColor[context, grey];
ENDCASE => Graphics.SetColor[context, black];
[] ← Graphics.SetFat[context, TRUE];
Graphics.DrawStroke[self: context, path: path];
};
IF segment # NIL THEN DrawInViewer[pathViewer, DoDrawSegment];
};
END.