diff options
| -rw-r--r-- | editor/pamscale.c | 79 |
1 files changed, 47 insertions, 32 deletions
diff --git a/editor/pamscale.c b/editor/pamscale.c index 82f4209f..09b61ed0 100644 --- a/editor/pamscale.c +++ b/editor/pamscale.c @@ -751,21 +751,28 @@ parseCommandLine(int argc, static void computeOutputDimensions(struct cmdlineInfo const cmdline, - unsigned int const rows, unsigned int const cols, - int * const newrowsP, - int * const newcolsP) { + unsigned int const rows, + int * const newcolsP, + int * const newrowsP) { + + double newcolsD, newrowsD; + /* Intermediate calculation of the output dimensions, in double + precision floating point to avoid arithmetic overflow. + */ + unsigned int newcols, newrows; + /* The output dimensions we return */ switch(cmdline.scaleType) { case SCALE_PIXELMAX: { if (rows * cols <= cmdline.pixels) { - *newrowsP = rows; - *newcolsP = cols; + newrowsD = rows; + newcolsD = cols; } else { const double scale = sqrt( (float) cmdline.pixels / ((float) cols * (float) rows)); - *newrowsP = rows * scale; - *newcolsP = cols * scale; + newrowsD = rows * scale; + newcolsD = cols * scale; } } break; case SCALE_BOXFIT: @@ -778,48 +785,56 @@ computeOutputDimensions(struct cmdlineInfo const cmdline, cmdline.scaleType == SCALE_BOXFIT) || (box_aspect_ratio < aspect_ratio && cmdline.scaleType == SCALE_BOXFILL)) { - *newrowsP = cmdline.ysize; - *newcolsP = *newrowsP * aspect_ratio + 0.5; + newrowsD = cmdline.ysize; + newcolsD = newrowsD * aspect_ratio; } else { - *newcolsP = cmdline.xsize; - *newrowsP = *newcolsP / aspect_ratio + 0.5; + newcolsD = cmdline.xsize; + newrowsD = newcolsD / aspect_ratio; } } break; case SCALE_SEPARATE: { if (cmdline.xsize) - *newcolsP = cmdline.xsize; + newcolsD = cmdline.xsize; else if (cmdline.xscale) - *newcolsP = cmdline.xscale * cols + .5; + newcolsD = cmdline.xscale * cols; else if (cmdline.ysize) - *newcolsP = cols * ((float) cmdline.ysize/rows) +.5; + newcolsD = cols * ((float) cmdline.ysize/rows); else - *newcolsP = cols; + newcolsD = cols; if (cmdline.ysize) - *newrowsP = cmdline.ysize; + newrowsD = cmdline.ysize; else if (cmdline.yscale) - *newrowsP = cmdline.yscale * rows +.5; + newrowsD = cmdline.yscale * rows; else if (cmdline.xsize) - *newrowsP = rows * ((float) cmdline.xsize/cols) +.5; + newrowsD = rows * ((float) cmdline.xsize/cols); else - *newrowsP = rows; + newrowsD = rows; } } - - /* If the calculations above yielded (due to rounding) a zero - * dimension, we fudge it up to 1. We do this rather than considering - * it a specification error (and dying) because it's friendlier to - * automated processes that work on arbitrary input. It saves them - * having to check their numbers to avoid catastrophe. - */ - - if (*newcolsP < 1) *newcolsP = 1; - if (*newrowsP < 1) *newrowsP = 1; + + /* If the rounding yields a zero dimension, we fudge it up to 1. We do + this rather than considering it a specification error (and dying) + because it's friendlier to automated processes that work on arbitrary + input. It saves them having to check their numbers to avoid + catastrophe. + */ + newcols = MAX(1, ROUNDU(newcolsD)); + newrows = MAX(1, ROUNDU(newrowsD)); + + if (newcols > INT_MAX - 2) + pm_error("output image width (%u) too large for computations", + newcols); + if (newrows > INT_MAX - 2) + pm_error("output image height (%u) too large for computation", + newrows); + + *newcolsP = newcols; + *newrowsP = newrows; } - /****************************/ /****************************/ /******* resampling *********/ @@ -2142,8 +2157,8 @@ pamscale(FILE * const ifP, outpam.maxval = inpam.maxval; } - computeOutputDimensions(cmdline, inpam.height, inpam.width, - &outpam.height, &outpam.width); + computeOutputDimensions(cmdline, inpam.width, inpam.height, + &outpam.width, &outpam.height); xscale = (float) outpam.width / inpam.width; yscale = (float) outpam.height / inpam.height; |