mipmap.c

winNT技术操作系统,国外开放的原代码和LIUX一样

    float percent;
    /* Max components in a format is 4, so... */
    float totals[4];
    float area;
    int i,j,k,yint,xint,xindex,yindex;
    int temp;

    if (widthin == widthout*2 && heightin == heightout*2) {
	halveImage(components, widthin, heightin, datain, dataout);
	return;
    }
    convy = (float) heightin/heightout;
    convx = (float) widthin/widthout;
    halfconvx = convx/2;
    halfconvy = convy/2;
    for (i = 0; i < heightout; i++) {
	y = convy * (i+0.5);
	if (heightin > heightout) {
	    highy = y + halfconvy;
	    lowy = y - halfconvy;
	} else {
	    highy = y + 0.5;
	    lowy = y - 0.5;
	}
	for (j = 0; j < widthout; j++) {
	    x = convx * (j+0.5);
	    if (widthin > widthout) {
		highx = x + halfconvx;
		lowx = x - halfconvx;
	    } else {
		highx = x + 0.5;
		lowx = x - 0.5;
	    }

	    /*
	    ** Ok, now apply box filter to box that goes from (lowx, lowy)
	    ** to (highx, highy) on input data into this pixel on output
	    ** data.
	    */
	    totals[0] = totals[1] = totals[2] = totals[3] = 0.0;
	    area = 0.0;

	    y = lowy;
	    yint = floor(y);
	    while (y < highy) {
		yindex = (yint + heightin) % heightin;
		if (highy < yint+1) {
		    ypercent = highy - y;
		} else {
		    ypercent = yint+1 - y;
		}

		x = lowx;
		xint = floor(x);

		while (x < highx) {
		    xindex = (xint + widthin) % widthin;
		    if (highx < xint+1) {
			xpercent = highx - x;
		    } else {
			xpercent = xint+1 - x;
		    }

		    percent = xpercent * ypercent;
		    area += percent;
		    temp = (xindex + (yindex * widthin)) * components;
		    for (k = 0; k < components; k++) {
			totals[k] += datain[temp + k] * percent;
		    }

		    xint++;
		    x = xint;
		}
		yint++;
		y = yint;
	    }

	    temp = (j + (i * widthout)) * components;
	    for (k = 0; k < components; k++) {
		/* totals[] should be rounded in the case of enlarging an RGB
		 * ramp when the type is 332 or 4444
		 */
		dataout[temp + k] = (totals[k]+0.5)/area;
	    }
	}
    }
}

static void scale_internal_ubyte(GLint components, GLint widthin,
			   GLint heightin, const GLubyte *datain,
			   GLint widthout, GLint heightout,
			   GLubyte *dataout, GLint element_size,
			   GLint ysize, GLint group_size)
{
    float convx;
    float convy;
    float percent;
    /* Max components in a format is 4, so... */
    float totals[4];
    float area;
    int i,j,k,xindex;

    const char *temp, *temp0;
    const char *temp_index;
    int outindex;

    int lowx_int, highx_int, lowy_int, highy_int;
    float x_percent, y_percent;
    float lowx_float, highx_float, lowy_float, highy_float;
    float convy_float, convx_float;
    int convy_int, convx_int;
    int l, m;
    const char *left, *right;

    if (widthin == widthout*2 && heightin == heightout*2) {
	halveImage_ubyte(components, widthin, heightin,
	(const GLubyte *)datain, (GLubyte *)dataout,
	element_size, ysize, group_size);
	return;
    }
    convy = (float) heightin/heightout;
    convx = (float) widthin/widthout;
    convy_int = floor(convy);
    convy_float = convy - convy_int;
    convx_int = floor(convx);
    convx_float = convx - convx_int;

    area = convx * convy;

    lowy_int = 0;
    lowy_float = 0;
    highy_int = convy_int;
    highy_float = convy_float;

    for (i = 0; i < heightout; i++) {
	lowx_int = 0;
	lowx_float = 0;
	highx_int = convx_int;
	highx_float = convx_float;

	for (j = 0; j < widthout; j++) {

	    /*
	    ** Ok, now apply box filter to box that goes from (lowx, lowy)
	    ** to (highx, highy) on input data into this pixel on output
	    ** data.
	    */
	    totals[0] = totals[1] = totals[2] = totals[3] = 0.0;

	    /* calculate the value for pixels in the 1st row */
	    xindex = lowx_int*group_size;
	    if((highy_int>lowy_int) && (highx_int>lowx_int)) {

		y_percent = 1-lowy_float;
		temp = (const char *)datain + xindex + lowy_int * ysize;
		percent = y_percent * (1-lowx_float);
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * percent;
		}
		left = temp;
		for(l = lowx_int+1; l < highx_int; l++) {
		    temp += group_size;
		    for (k = 0, temp_index = temp; k < components;
			 k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * y_percent;
		    }
		}
		temp += group_size;
		right = temp;
		percent = y_percent * highx_float;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * percent;
		}

		/* calculate the value for pixels in the last row */	        
		y_percent = highy_float;
		percent = y_percent * (1-lowx_float);
		temp = (const char *)datain + xindex + highy_int * ysize;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * percent;
		}
		for(l = lowx_int+1; l < highx_int; l++) {
		    temp += group_size;
		    for (k = 0, temp_index = temp; k < components;
			 k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * y_percent;
		    }
		}
		temp += group_size;
		percent = y_percent * highx_float;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * percent;
		}


		/* calculate the value for pixels in the 1st and last column */
		for(m = lowy_int+1; m < highy_int; m++) {
		    left += ysize;
		    right += ysize;
		    for (k = 0; k < components;
			 k++, left += element_size, right += element_size) {
			totals[k] += (GLubyte)(*(left))*(1-lowx_float)
				+(GLubyte)(*(right))*highx_float;
		    }
		}
	    } else if (highy_int > lowy_int) {
		x_percent = highx_float - lowx_float;
		percent = (1-lowy_float)*x_percent;
		temp = (const char *)datain + xindex + lowy_int*ysize;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * percent;
		}
		for(m = lowy_int+1; m < highy_int; m++) {
		    temp += ysize;
		    for (k = 0, temp_index = temp; k < components;
			 k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * x_percent;
		    }
		}
		percent = x_percent * highy_float;
		temp += ysize;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * percent;
		}
	    } else if (highx_int > lowx_int) {
		y_percent = highy_float - lowy_float;
		percent = (1-lowx_float)*y_percent;
		temp = (const char *)datain + xindex + lowy_int*ysize;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * percent;
		}
		for (l = lowx_int+1; l < highx_int; l++) {
		    temp += group_size;
		    for (k = 0, temp_index = temp; k < components;
			 k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * y_percent;
		    }
		}
		temp += group_size;
		percent = y_percent * highx_float;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * percent;
		}
	    } else {
		percent = (highy_float-lowy_float)*(highx_float-lowx_float);
		temp = (const char *)datain + xindex + lowy_int * ysize;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index)) * percent;
		}
	    }



	    /* this is for the pixels in the body */
	    temp0 = (const char *)datain + xindex + group_size +
		 (lowy_int+1)*ysize;
	    for (m = lowy_int+1; m < highy_int; m++) {
		temp = temp0;
		for(l = lowx_int+1; l < highx_int; l++) {
		    for (k = 0, temp_index = temp; k < components;
			 k++, temp_index += element_size) {
			totals[k] += (GLubyte)(*(temp_index));
		    }
		    temp += group_size;
		}
		temp0 += ysize;
	    }

	    outindex = (j + (i * widthout)) * components;
	    for (k = 0; k < components; k++) {
		dataout[outindex + k] = totals[k]/area;
		/*printf("totals[%d] = %f\n", k, totals[k]);*/
	    }
	    lowx_int = highx_int;
	    lowx_float = highx_float;
	    highx_int += convx_int;
	    highx_float += convx_float;
	    if(highx_float > 1) {
		highx_float -= 1.0;
		highx_int++;
	    }
	}
	lowy_int = highy_int;
	lowy_float = highy_float;
	highy_int += convy_int;
	highy_float += convy_float;
	if(highy_float > 1) {
	    highy_float -= 1.0;
	    highy_int++;
	}
    }
}

static void scale_internal_byte(GLint components, GLint widthin,
			   GLint heightin, const GLbyte *datain,
			   GLint widthout, GLint heightout,
			   GLbyte *dataout, GLint element_size,
			   GLint ysize, GLint group_size)
{
    float convx;
    float convy;
    float percent;
    /* Max components in a format is 4, so... */
    float totals[4];
    float area;
    int i,j,k,xindex;

    const char *temp, *temp0;
    const char *temp_index;
    int outindex;

    int lowx_int, highx_int, lowy_int, highy_int;
    float x_percent, y_percent;
    float lowx_float, highx_float, lowy_float, highy_float;
    float convy_float, convx_float;
    int convy_int, convx_int;
    int l, m;
    const char *left, *right;

    if (widthin == widthout*2 && heightin == heightout*2) {
	halveImage_byte(components, widthin, heightin,
	(const GLbyte *)datain, (GLbyte *)dataout,
	element_size, ysize, group_size);
	return;
    }
    convy = (float) heightin/heightout;
    convx = (float) widthin/widthout;
    convy_int = floor(convy);
    convy_float = convy - convy_int;
    convx_int = floor(convx);
    convx_float = convx - convx_int;

    area = convx * convy;

    lowy_int = 0;
    lowy_float = 0;
    highy_int = convy_int;
    highy_float = convy_float;

    for (i = 0; i < heightout; i++) {
	lowx_int = 0;
	lowx_float = 0;
	highx_int = convx_int;
	highx_float = convx_float;

	for (j = 0; j < widthout; j++) {

	    /*
	    ** Ok, now apply box filter to box that goes from (lowx, lowy)
	    ** to (highx, highy) on input data into this pixel on output
	    ** data.
	    */
	    totals[0] = totals[1] = totals[2] = totals[3] = 0.0;

	    /* calculate the value for pixels in the 1st row */
	    xindex = lowx_int*group_size;
	    if((highy_int>lowy_int) && (highx_int>lowx_int)) {

		y_percent = 1-lowy_float;
		temp = (const char *)datain + xindex + lowy_int * ysize;
		percent = y_percent * (1-lowx_float);
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLbyte)(*(temp_index)) * percent;
		}
		left = temp;
		for(l = lowx_int+1; l < highx_int; l++) {
		    temp += group_size;
		    for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLbyte)(*(temp_index)) * y_percent;
		    }
		}
		temp += group_size;
		right = temp;
		percent = y_percent * highx_float;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLbyte)(*(temp_index)) * percent;
		}

		/* calculate the value for pixels in the last row */	        
		y_percent = highy_float;
		percent = y_percent * (1-lowx_float);
		temp = (const char *)datain + xindex + highy_int * ysize;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLbyte)(*(temp_index)) * percent;
		}
		for(l = lowx_int+1; l < highx_int; l++) {
		    temp += group_size;
		    for (k = 0, temp_index = temp; k < components;
			 k++, temp_index += element_size) {
			totals[k] += (GLbyte)(*(temp_index)) * y_percent;
		    }
		}
		temp += group_size;
		percent = y_percent * highx_float;
		for (k = 0, temp_index = temp; k < components;
		     k++, temp_index += element_size) {
			totals[k] += (GLbyte)(*(temp_index)) * percent;
		}


		/* calculate the value for pixels in the 1st and last column */
		for(m = lowy_int+1; m < highy_int; m++) {
		    left += ysize;
		    right += ysize;
		    for (k = 0; k < components;
			 k++, left += element_size, right += element_size) {
			totals[k] += (GLbyte)(*(left))*(1-lowx_float)
				+(GLbyte)(*(right))*highx_float;
		    }
		}
	    } else if (highy_int > lowy_int) {
		x_percent = highx_float - lowx_float;
		percent = (1-lowy_float)*x_percent;