img.c

kaffe Java 解释器语言,源码,Java的子集系统,开放源代码

/**
 * img.c - 
 *
 * Copyright (c) 1998
 *      Transvirtual Technologies, Inc.  All rights reserved.
 *
 * See the file "license.terms" for information on usage and redistribution 
 * of this file. 
 */


#include "toolkit.h"


/* interfaces of image conversion functions */
Image* readGifFile ( int fd );
Image* readGifData ( unsigned char*, long len );
Image* readJpegFile ( int fd );
Image* readJpegData ( unsigned char*, long len );
Image* readPngFile ( int fd );
Image* readPngData ( unsigned char*, long len );

/************************************************************************************
 * own auxiliary funcs
 */

Image*
createImage ( int width, int height )
{
  Image * img = AWT_CALLOC( 1, sizeof( Image));

  img->trans  = -1;     /* default to no alpha */

  img->width = width;   /* we need to (temp) store them for subsequent X image creation */
  img->height = height;

  return img;
}

static int
createShmXImage ( Toolkit* X, Image* img, int depth, int isMask )
{
#if defined(USE_XSHM_EXTENSION)
  Visual  *vis = DefaultVisual( X->dsp, DefaultScreen( X->dsp));
  XShmSegmentInfo* shmi = (XShmSegmentInfo*) AWT_MALLOC( sizeof(XShmSegmentInfo));
  XImage *xim;
  unsigned int    nBytes;

  if ( isMask ) {
	xim = XShmCreateImage( X->dsp, vis, depth, XYBitmap, 0, shmi, img->width, img->height);
  }
  else {
    xim = XShmCreateImage( X->dsp, vis, depth, ZPixmap, 0, shmi, img->width, img->height);
  }

  nBytes = xim->bytes_per_line * img->height;
  shmi->shmid = shmget( IPC_PRIVATE, nBytes, (IPC_CREAT | 0777));

  /*
   * It is essential to check if shmget failed, because shared memory is usually
   * a scarce resource
   */
  if ( shmi->shmid == -1 ) {
	XShmDetach( X->dsp, shmi);
	xim->data = 0;
	XDestroyImage( xim);
	AWT_FREE( shmi);

	X->shm = SUSPEND_SHM;
	return 0;
  }

  xim->data = shmi->shmaddr = shmat( shmi->shmid, 0, 0);
  shmi->readOnly = False;
  XShmAttach( X->dsp, shmi);
  /*
   * make sure it will be freed automatically once the attachment count comes
   * down to 0 (either by explicit imgFreeImage or by process termination)
   */
  shmctl( shmi->shmid, IPC_RMID, 0);

  if ( isMask ) {
	memset( xim->data, 0xff, nBytes);
	img->shmiMask = shmi;
	img->xMask = xim;
  }
  else {
	img->shmiImg = shmi;
	img->xImg = xim;
  }

  return 1;
#else
  return 0;
#endif
}


static void
destroyShmXImage ( Toolkit* X, Image* img, int isMask )
{
#if defined(USE_XSHM_EXTENSION)
  XShmSegmentInfo *shmi;
  XImage          *xim;

  if ( isMask ) {
	shmi = img->shmiMask;
	xim  = img->xMask;
	img->shmiMask = 0;
  }
  else {
	shmi = img->shmiImg;
	xim  = img->xImg;
	img->shmiImg = 0;
  }

  XShmDetach( X->dsp, shmi);
  xim->data = 0;
  XDestroyImage( xim);
  /* we created it as 'deleted', so we just have to detach here */
  shmdt( shmi->shmaddr);
  AWT_FREE( shmi);

  /* if we have suspended shm, give it a try again */
  if ( X->shm == SUSPEND_SHM )
	X->shm = USE_SHM;
#endif
}



void
createXImage ( Toolkit* X, Image* img )
{
  int bitmap_pad;
  int bytes_per_line;
  int bytes_per_pix;
  unsigned int nPix;
  char *data;
  Visual *vis  = DefaultVisual( X->dsp, DefaultScreen( X->dsp));
  int    depth = DefaultDepth(  X->dsp, DefaultScreen( X->dsp));
	
  if ( depth <= 8)	      bytes_per_pix = 1;
  else if ( depth <= 16)  bytes_per_pix = 2;
  else			          bytes_per_pix = 4;

  bytes_per_line = bytes_per_pix * img->width;
  bitmap_pad = bytes_per_pix * 8;
  nPix = img->width * img->height;

  if ( (X->shm == USE_SHM) && (nPix > X->shmThreshold) && (img->alpha == 0) ) {
	if ( createShmXImage( X, img, depth, False) ){
	  DBG( AWT_IMG, printf("alloc Shm: %p %p %p (%dx%d) \n", img, img->xImg, img->shmiImg,
					  img->width, img->height));
	  return;
	}
  }

  data = AWT_CALLOC( nPix, bytes_per_pix);
  img->xImg = XCreateImage( X->dsp, vis, depth, ZPixmap, 0,
							data, img->width, img->height, bitmap_pad, bytes_per_line);
  DBG( AWT_IMG, printf( "alloc: %p %p (%dx%d)\n", img, img->xImg, img->width, img->height));
}

void
createXMaskImage ( Toolkit* X, Image* img )
{
  int     bytes_per_line;
  unsigned int nBytes, nPix;
  char    *data;
  Visual  *vis = DefaultVisual( X->dsp, DefaultScreen( X->dsp));

  bytes_per_line = (img->width + 7) / 8;
  nPix   = img->width * img->height;
  nBytes = bytes_per_line * img->height;

  if ( (X->shm == USE_SHM) && (nPix > X->shmThreshold) ) {
	if ( createShmXImage( X, img, 1, True) ){
	  DBG( AWT_IMG, printf( "alloc Shm mask: %p %p %p (%dx%d) \n", img, img->xMask, img->shmiMask,
					  img->width, img->height));
	  return;
	}
  }

  data = AWT_MALLOC( nBytes);
  memset( data, 0xff, nBytes);

  img->xMask = XCreateImage( X->dsp, vis, 1, XYBitmap, 0,
							 data, img->width, img->height, 8, bytes_per_line );
  DBG( AWT_IMG, printf( "alloc mask: %p %p (%dx%d)\n", img, img->xMask, img->width, img->height));
}


void
createAlphaImage ( Toolkit* X, Image *img )
{
  int nBytes = img->width * img->height;

  img->alpha = AWT_MALLOC( sizeof( AlphaImage));

  img->alpha->width  = img->width;
  img->alpha->height = img->height;
  img->alpha->buf = AWT_MALLOC( nBytes);
  memset( img->alpha->buf, 0xff, nBytes);
}

/*
 * For images with a full alpha channel, check if we really need an alpha byte for
 * each pel, or if a mask bitmap (alpha 0x00 / 0xff) will be sufficient
 */
int
needsFullAlpha ( Toolkit* X, Image *img, double threshold )
{
  int i, j, a;
  int n = 0, max;

  if ( !img->alpha ) return 0;

  max = (img->width * img->height) * threshold;

  for ( i=0; i<img->height; i++ ) {
	for ( j=0; j<img->width; j++ ) {
	  a = GetAlpha( img->alpha, j, i);
	  if ( (a != 0) && (a != 0xff) ) {
		if ( ++n > max )
		  return 1;
	  }
	}
  }

  return 0;
}

/*
 * A full alpha image channel is way slower than using a mask bitmap (= 0 / 0xff alpha).
 * This function provides a simple alpha-to-mask translation
 */
/* also used in imgpng */
void
reduceAlpha ( Toolkit* X, Image* img, int threshold )
{
  int i, j, a;

  if ( !img->alpha )
	return;

  createXMaskImage( X, img);

  for ( i=0; i<img->height; i++ ) {
	for ( j=0; j<img->width; j++ ) {
	  a = GetAlpha( img->alpha, j, i);
	  if ( a < threshold ) {
		XPutPixel( img->xImg, j, i, 0);
		XPutPixel( img->xMask, j, i, 0);
	  }
	}
  }

  AWT_FREE( img->alpha->buf);
  AWT_FREE( img->alpha);
  img->alpha = 0;
}


static inline int
interpolate ( int ul, int ur, int ll, int lr, double dx, double dy )
{
  double u = ul + (double)(ur - ul) * dx;
  double l = ll + (double)(lr - ll) * dx;

  return (int) (u + (l - u) * dy  + 0.5);
}

static unsigned int
getScaledAlpha ( Toolkit* X, Image* img, int x, int y, double dx, double dy )
{
  int   ul, ur, ll, lr, a;
  int   xi = (dx) ? x+1 : x;
  int   yi = (dy) ? y+1 : y;

  if ( img->alpha ) {
	ul = GetAlpha( img->alpha, x, y);
	ur = GetAlpha( img->alpha, xi, y);
	ll = GetAlpha( img->alpha, x, yi);
	lr = GetAlpha( img->alpha, xi,yi);
	a = (unsigned int) interpolate( ul, ur, ll, lr, dx, dy);
	return a;
  }

  return 0xff;
}

static long
getScaledPixel ( Toolkit* X, Image* img, int x, int y, double dx, double dy )
{
  unsigned long  ul, ur, ll, lr;
  int            ulR, urR, llR, lrR, ulG, urG, llG, lrG, ulB, urB, llB, lrB, r, g, b;
  int            xi = (dx) ? x+1 : x;
  int            yi = (dy) ? y+1 : y;

  if ( img->xMask ) {
	ul = XGetPixel( img->xMask, x, y);
	ur = XGetPixel( img->xMask, xi, y);
	ll = XGetPixel( img->xMask, x, yi);
	lr = XGetPixel( img->xMask, xi,yi);
	
	if ( !interpolate( ul, ur, ll, lr, dx, dy) )
	  return -1;
  }

  ul = XGetPixel( img->xImg, x, y);
  ur = XGetPixel( img->xImg, xi, y);
  ll = XGetPixel( img->xImg, x, yi);
  lr = XGetPixel( img->xImg, xi,yi);


  if ( (ul == ur) && (ll == ul) && (lr == ll) ) {
	rgbValues( X, ul, &r, &g, &b);
  }
  else {
	rgbValues( X, ul, &ulR, &ulG, &ulB);
	rgbValues( X, ur, &urR, &urG, &urB);
	rgbValues( X, ll, &llR, &llG, &llB);
	rgbValues( X, lr, &lrR, &lrG, &lrB);

	r = interpolate( ulR, urR, llR, lrR, dx, dy);
	g = interpolate( ulG, urG, llG, lrG, dx, dy);
	b = interpolate( ulB, urB, llB, lrB, dx, dy);
  }

  return pixelValue( X, (r << 16) | (g << 8) | b);
}



void
initScaledImage ( Toolkit* X, Image *tgt, Image *src,
				  int dx0, int dy0, int dx1, int dy1,
				  int sx0, int sy0, int sx1, int sy1 )
{
  double         xScale, yScale, sX, sY, sxDelta, syDelta;
  int            dx, dy, dxInc, dyInc, sx, sy;
  long           c;

  dxInc = (dx1 > dx0) ? 1 : -1;
  dyInc = (dy1 > dy0) ? 1 : -1;

  dx1 += dxInc;
  dy1 += dyInc;

  xScale = (double) (dx1 - dx0) / (double) (sx1 - sx0 +1);
  yScale = (double) (dy1 - dy0) / (double) (sy1 - sy0 +1);

  for ( dy=dy0; dy != dy1; dy += dyInc ) {
	sY = sy0 + (dy - dy0) / yScale;
	sy = (int) sY;
	syDelta = (sy < (sy1-1)) ? sY - sy : 0;

	for ( dx=dx0; dx != dx1; dx += dxInc ) {
	  sX = sx0 + (dx - dx0) / xScale;
	  sx = (int) sX;
	  sxDelta = (sx < (sx1-1)) ? sX - sx : 0;

	  if ( (c = getScaledPixel( X, src, sx, sy, sxDelta, syDelta)) != -1 ){
  		XPutPixel( tgt->xImg, dx, dy, c);
		if ( src->alpha )
		  PutAlpha( tgt->alpha, dx, dy, getScaledAlpha( X, src, sx, sy, sxDelta, syDelta));
	  }
	  else {
		XPutPixel( tgt->xMask, dx, dy, 0);
		XPutPixel( tgt->xImg, dx, dy, 0);
	  }
	}
  }
}


/************************************************************************************
 * exported native methods
 */


void*
Java_java_awt_Toolkit_imgCreateImage ( JNIEnv* env, jclass clazz, jint width, jint height )
{
  Image *img = createImage( width, height);
  createXImage( X, img);
  return img;
}


void*
Java_java_awt_Toolkit_imgCreateScreenImage ( JNIEnv* env, jclass clazz, jint width, jint height )
{
  Image  *img = createImage( width, height);
  int    depth = DefaultDepth(  X->dsp, DefaultScreen( X->dsp));

  img->pix  = XCreatePixmap( X->dsp, X->root, width, height, depth);
  return img;
}