src/scratchpad/src/org/apache/poi/hwmf/record/WmfSetMapMode.java

package org.apache.poi.hwmf.record;

import java.io.IOException;

import org.apache.poi.util.LittleEndianConsts;
import org.apache.poi.util.LittleEndianInputStream;

/**
 * The META_SETMAPMODE record defines the mapping mode in the playback device context.
 * The mapping mode defines the unit of measure used to transform page-space units into
 * device-space units, and also defines the orientation of the device's x and y axes. 
 */
public class WmfSetMapMode implements WmfRecord {
    
    /**
     * A 16-bit unsigned integer that defines the mapping mode.
     * 
     * The MapMode defines how logical units are mapped to physical units;
     * that is, assuming that the origins in both the logical and physical coordinate systems
     * are at the same point on the drawing surface, what is the physical coordinate (x',y')
     * that corresponds to logical coordinate (x,y).
     * 
     * For example, suppose the mapping mode is MM_TEXT. Given the following definition of that
     * mapping mode, and an origin (0,0) at the top left corner of the drawing surface, logical
     * coordinate (4,5) would map to physical coordinate (4,5) in pixels.
     * 
     * Now suppose the mapping mode is MM_LOENGLISH, with the same origin as the previous
     * example. Given the following definition of that mapping mode, logical coordinate (4,-5)
     * would map to physical coordinate (0.04,0.05) in inches.
     * 
     * This MUST be one of the following:
     * 
     * MM_TEXT (= 0x0001):
     *  Each logical unit is mapped to one device pixel.
     *  Positive x is to the right; positive y is down.
     *  
     * MM_LOMETRIC (= 0x0002):
     *  Each logical unit is mapped to 0.1 millimeter.
     *  Positive x is to the right; positive y is up.
     *
     * MM_HIMETRIC (= 0x0003):
     *  Each logical unit is mapped to 0.01 millimeter.
     *  Positive x is to the right; positive y is up.
     *
     * MM_LOENGLISH (= 0x0004):
     *  Each logical unit is mapped to 0.01 inch.
     *  Positive x is to the right; positive y is up.
     * 
     * MM_HIENGLISH (= 0x0005):
     *  Each logical unit is mapped to 0.001 inch.
     *  Positive x is to the right; positive y is up.
     * 
     * MM_TWIPS (= 0x0006):
     *  Each logical unit is mapped to one twentieth (1/20) of a point.
     *  In printing, a point is 1/72 of an inch; therefore, 1/20 of a point is 1/1440 of an inch.
     *  This unit is also known as a "twip".
     *  Positive x is to the right; positive y is up.
     *
     * MM_ISOTROPIC (= 0x0007):
     *  Logical units are mapped to arbitrary device units with equally scaled axes;
     *  that is, one unit along the x-axis is equal to one unit along the y-axis.
     *  The META_SETWINDOWEXT and META_SETVIEWPORTEXT records specify the units and the
     *  orientation of the axes.
     *  The processing application SHOULD make adjustments as necessary to ensure the x and y
     *  units remain the same size. For example, when the window extent is set, the viewport
     *  SHOULD be adjusted to keep the units isotropic.
     *
     * MM_ANISOTROPIC (= 0x0008):
     *  Logical units are mapped to arbitrary units with arbitrarily scaled axes.
     */
    int mapMode;
    
    public WmfRecordType getRecordType() {
        return WmfRecordType.setMapMode;
    }
    
    public int init(LittleEndianInputStream leis, long recordSize, int recordFunction) throws IOException {
        mapMode = leis.readUShort();
        return LittleEndianConsts.SHORT_SIZE;
    }
}