/*

Copyright by Greg Ross, 2008

This file is part of Magic Table.

Magic Table is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Magic Table is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Magic Table.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * This class renders cells when the fisheye feature is switched on.
 * @author Greg Ross
 * @constructor
 * @param tableModel
 * @param colourRamp the colour ramp from which the cell's back colour will be derived.
 */
greg.ross.visualisation.FisheyeCellRenderer = function(tableModel, colourRamp)
{
	var colourGradient;
	var defaultCellBackgroundColour = 'rgb(255, 255, 255)';
	var gridColour = 'rgb(0, 0, 0)';
	
	function init()
	{
		colourGradient = greg.ross.visualisation.TableGradientColourProvider.createGradient(tableModel, colourRamp);
	}
	
	function renderCellText(canvasContext, cellValue, tlX, tlY, trX, trY, brX, brY, blX, blY)
	{
		if (cellValue == null) return;
		
		var sValue = cellValue + "";
		var font = "sans";
	  	var fontsize = 10;
		var centerPoint = greg.ross.visualisation.TableGeometry.getCentre(tlX, tlY, trX, trY, brX, brY, blX, blY);
		canvasContext.drawTextCenter(font, fontsize, centerPoint.x, centerPoint.y, sValue);
	}
	
	/**
	 * The fisheye table calls this method to render the cell. Classes that extend a cell renderer
	 * must implement this method.
	 * @member greg.ross.visualisation.FisheyeCellRenderer
	 * @param canvasContext the canvas context
	 * @param column the column index
	 * @param cellCoordinates the coordinates defining the cell poylgon
	 * @param cellValue the value ot be rendered in the cell
	 * @param barFillEnabled true if the bar-fill feature is turned on
	 * @param cellWidth the width of the cell
	 * @param rowGradientEnabled true if the cells are to be coloured according to row min and max values instead of globals
	 */
	this.drawCell = function(canvasContext, column, row, cellCoordinates, cellValue, barFillEnabled, cellWidth, rowGradientEnabled)
	{
		var colr;
		
		if (rowGradientEnabled)
			colr = greg.ross.visualisation.TableGradientColourProvider.getColourFromValue(tableModel.getColourGradientForRow(row), cellValue, defaultCellBackgroundColour);
		else
			colr = greg.ross.visualisation.TableGradientColourProvider.getColourFromValue(colourGradient, cellValue, defaultCellBackgroundColour);
		
		if (!barFillEnabled) 
		{
			canvasContext.fillStyle = colr;
			canvasContext.beginPath();
			canvasContext.moveTo(cellCoordinates.x1, cellCoordinates.y1);
			canvasContext.lineTo(cellCoordinates.x2, cellCoordinates.y2);
			canvasContext.lineTo(cellCoordinates.x3, cellCoordinates.y3);
			canvasContext.lineTo(cellCoordinates.x4, cellCoordinates.y4);
			canvasContext.lineTo(cellCoordinates.x1, cellCoordinates.y1);
			canvasContext.fill();
			
			canvasContext.strokeStyle = gridColour;
			canvasContext.lineWidth = 0.5;
			canvasContext.stroke();
		}
		else
		{
			// Fill polygon background for fisheye cell.
			canvasContext.fillStyle = defaultCellBackgroundColour;
			canvasContext.beginPath();
			canvasContext.moveTo(cellCoordinates.x1, cellCoordinates.y1);
			canvasContext.lineTo(cellCoordinates.x2, cellCoordinates.y2);
			canvasContext.lineTo(cellCoordinates.x3, cellCoordinates.y3);
			canvasContext.lineTo(cellCoordinates.x4, cellCoordinates.y4);
			canvasContext.lineTo(cellCoordinates.x1, cellCoordinates.y1);
			canvasContext.fill();
			
			canvasContext.strokeStyle = gridColour;
			canvasContext.lineWidth = 0.5;
			canvasContext.stroke();
			
			// Calculate and fill polygon according to cell value.
			var widthFraction = greg.ross.visualisation.TableMath.calculateBarWidthFraction(tableModel, cellValue, cellWidth, column);
			
			canvasContext.fillStyle = colr;
			canvasContext.beginPath();
			canvasContext.moveTo(cellCoordinates.x1, cellCoordinates.y1);
			
			var dx = parseFloat((cellCoordinates.x2 - cellCoordinates.x1) * widthFraction) + cellCoordinates.x1;
			var dy = parseFloat((cellCoordinates.y2 - cellCoordinates.y1) * widthFraction) +  cellCoordinates.y1;
			canvasContext.lineTo(dx, dy);
			
			dx =  parseFloat((cellCoordinates.x3 - cellCoordinates.x4) * widthFraction) + cellCoordinates.x4;
			dy = parseFloat((cellCoordinates.y3 - cellCoordinates.y4) * widthFraction) + cellCoordinates.y4;
			
			canvasContext.lineTo(dx, dy-0.5);
			canvasContext.lineTo(cellCoordinates.x4, cellCoordinates.y4-0.5);
			canvasContext.lineTo(cellCoordinates.x1, cellCoordinates.y1);
			canvasContext.fill();
			
			// Stroke the path.			
			canvasContext.beginPath();
			canvasContext.moveTo(cellCoordinates.x1, cellCoordinates.y1);
			var dx = parseFloat((cellCoordinates.x2 - cellCoordinates.x1) * widthFraction) + cellCoordinates.x1;
			var dy = parseFloat((cellCoordinates.y2 - cellCoordinates.y1) * widthFraction) +  cellCoordinates.y1;
			canvasContext.lineTo(dx, dy);
			
			dx =  parseFloat((cellCoordinates.x3 - cellCoordinates.x4) * widthFraction) + cellCoordinates.x4;
			dy = parseFloat((cellCoordinates.y3 - cellCoordinates.y4) * widthFraction) + cellCoordinates.y4;
			
			canvasContext.moveTo(dx, dy);
			canvasContext.lineTo(cellCoordinates.x4, cellCoordinates.y4);
			canvasContext.lineTo(cellCoordinates.x1, cellCoordinates.y1);
			
			canvasContext.strokeStyle = gridColour;
			canvasContext.lineWidth = 0.5;
			canvasContext.stroke();
		}
		
		var cellArea = greg.ross.visualisation.TableGeometry.getArea(cellCoordinates.x1, cellCoordinates.y1, cellCoordinates.x2, cellCoordinates.y2, cellCoordinates.x3, cellCoordinates.y3, cellCoordinates.x4, cellCoordinates.y4);
		
		if (cellArea > 1500) 
			renderCellText(canvasContext, cellValue, cellCoordinates.x1, cellCoordinates.y1, cellCoordinates.x2, cellCoordinates.y2, cellCoordinates.x3, cellCoordinates.y3, cellCoordinates.x4, cellCoordinates.y4);
	}
	
	init();
}