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package jogamp.opengl.util.pngj;
/**
* Simple immutable wrapper for basic image info.
* <p>
* Some parameters are redundant, but the constructor receives an 'orthogonal'
* subset.
* <p>
* ref: http://www.w3.org/TR/PNG/#11IHDR
*/
public class ImageInfo {
// very big value ; actually we are ok with 2**22=4M, perhaps even more
private static final int MAX_COLS_ROWS_VAL = 1000000;
/**
* Cols= Image width, in pixels.
*/
public final int cols;
/**
* Rows= Image height, in pixels
*/
public final int rows;
/**
* Bits per sample (per channel) in the buffer (1-2-4-8-16). This is 8-16
* for RGB/ARGB images, 1-2-4-8 for grayscale. For indexed images, number of
* bits per palette index (1-2-4-8)
*/
public final int bitDepth;
/**
* Number of channels, as used internally: 3 for RGB, 4 for RGBA, 2 for GA
* (gray with alpha), 1 for grayscale or indexed.
*/
public final int channels;
/**
* Flag: true if has alpha channel (RGBA/GA)
*/
public final boolean alpha;
/**
* Flag: true if is grayscale (G/GA)
*/
public final boolean greyscale;
/**
* Flag: true if image is indexed, i.e., it has a palette
*/
public final boolean indexed;
/**
* Flag: true if image internally uses less than one byte per sample (bit
* depth 1-2-4)
*/
public final boolean packed;
/**
* Bits used for each pixel in the buffer: channel * bitDepth
*/
public final int bitspPixel;
/**
* rounded up value: this is only used internally for filter
*/
public final int bytesPixel;
/**
* ceil(bitspp*cols/8)
*/
public final int bytesPerRow;
/**
* Equals cols * channels
*/
public final int samplesPerRow;
/**
* Amount of "packed samples" : when several samples are stored in a single
* byte (bitdepth 1,2 4) they are counted as one "packed sample". This is
* less that samplesPerRow only when bitdepth is 1-2-4 (flag packed = true)
* <p>
* This equals the number of elements in the scanline array if working with
* packedMode=true
* <p>
* For internal use, client code should rarely access this.
*/
public final int samplesPerRowPacked;
/**
* Short constructor: assumes truecolor (RGB/RGBA)
*/
public ImageInfo(final int cols, final int rows, final int bitdepth, final boolean alpha) {
this(cols, rows, bitdepth, alpha, false, false);
}
/**
* Full constructor
*
* @param cols
* Width in pixels
* @param rows
* Height in pixels
* @param bitdepth
* Bits per sample, in the buffer : 8-16 for RGB true color and
* greyscale
* @param alpha
* Flag: has an alpha channel (RGBA or GA)
* @param grayscale
* Flag: is gray scale (any bitdepth, with or without alpha)
* @param indexed
* Flag: has palette
*/
public ImageInfo(final int cols, final int rows, final int bitdepth, final boolean alpha, final boolean grayscale, final boolean indexed) {
this.cols = cols;
this.rows = rows;
this.alpha = alpha;
this.indexed = indexed;
this.greyscale = grayscale;
if (greyscale && indexed)
throw new PngjException("palette and greyscale are mutually exclusive");
this.channels = (grayscale || indexed) ? (alpha ? 2 : 1) : (alpha ? 4 : 3);
// http://www.w3.org/TR/PNG/#11IHDR
this.bitDepth = bitdepth;
this.packed = bitdepth < 8;
this.bitspPixel = (channels * this.bitDepth);
this.bytesPixel = (bitspPixel + 7) / 8;
this.bytesPerRow = (bitspPixel * cols + 7) / 8;
this.samplesPerRow = channels * this.cols;
this.samplesPerRowPacked = packed ? bytesPerRow : samplesPerRow;
// several checks
switch (this.bitDepth) {
case 1:
case 2:
case 4:
if (!(this.indexed || this.greyscale))
throw new PngjException("only indexed or grayscale can have bitdepth=" + this.bitDepth);
break;
case 8:
break;
case 16:
if (this.indexed)
throw new PngjException("indexed can't have bitdepth=" + this.bitDepth);
break;
default:
throw new PngjException("invalid bitdepth=" + this.bitDepth);
}
if (cols < 1 || cols > MAX_COLS_ROWS_VAL)
throw new PngjException("invalid cols=" + cols + " ???");
if (rows < 1 || rows > MAX_COLS_ROWS_VAL)
throw new PngjException("invalid rows=" + rows + " ???");
}
@Override
public String toString() {
return "ImageInfo [cols=" + cols + ", rows=" + rows + ", bitDepth=" + bitDepth + ", channels=" + channels
+ ", bitspPixel=" + bitspPixel + ", bytesPixel=" + bytesPixel + ", bytesPerRow=" + bytesPerRow
+ ", samplesPerRow=" + samplesPerRow + ", samplesPerRowP=" + samplesPerRowPacked + ", alpha=" + alpha
+ ", greyscale=" + greyscale + ", indexed=" + indexed + ", packed=" + packed + "]";
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + (alpha ? 1231 : 1237);
result = prime * result + bitDepth;
result = prime * result + channels;
result = prime * result + cols;
result = prime * result + (greyscale ? 1231 : 1237);
result = prime * result + (indexed ? 1231 : 1237);
result = prime * result + rows;
return result;
}
@Override
public boolean equals(final Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
final ImageInfo other = (ImageInfo) obj;
if (alpha != other.alpha)
return false;
if (bitDepth != other.bitDepth)
return false;
if (channels != other.channels)
return false;
if (cols != other.cols)
return false;
if (greyscale != other.greyscale)
return false;
if (indexed != other.indexed)
return false;
if (rows != other.rows)
return false;
return true;
}
}
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