diff --git a/contrib/examples/simpleover.c b/contrib/examples/simpleover.c index d74cd978e..38bf83469 100644 --- a/contrib/examples/simpleover.c +++ b/contrib/examples/simpleover.c @@ -11,8 +11,8 @@ * combine the alpha channels and corresponding data. * * Finally read an output (background) PNG using the 24-bit RGB format (the - * PNG will be composited on green (0x00ff00) by default if it has an alpha - * channel) and apply the intermediate image generated above to specified + * PNG will be composited on green (#00ff00) by default if it has an alpha + * channel), and apply the intermediate image generated above to specified * locations in the image. * * The command line has the general format: @@ -21,7 +21,7 @@ * {--sprite=width,height,name {[--at=x,y] {sprite.png}}} * {--add=name {x,y}} * - * The --sprite and --add options may occur multiple times, they are executed + * The --sprite and --add options may occur multiple times. They are executed * in order. --add may refer to any sprite already read. * * This code is intended to show how to composite multiple images together @@ -107,8 +107,8 @@ sprite_op(const struct sprite *sprite, int x_offset, int y_offset, */ - /* Check for an x or y offset that pushes the image beyond the right or - * bottom of the sprite: + /* Check for an x or y offset that pushes any part of the image beyond the + * right or bottom of the sprite: */ if ((y_offset < 0 || (unsigned)/*SAFE*/y_offset < sprite->height) && (x_offset < 0 || (unsigned)/*SAFE*/x_offset < sprite->width)) @@ -153,7 +153,7 @@ sprite_op(const struct sprite *sprite, int x_offset, int y_offset, * * This is exact (and does not overflow) for all values of * x in the range 0..65535*65535. (Note that the calculation - * produces the closest integer, the maximum error is <0.5). + * produces the closest integer; the maximum error is <0.5). */ png_uint_32 tmp; @@ -185,8 +185,8 @@ sprite_op(const struct sprite *sprite, int x_offset, int y_offset, static int create_sprite(struct sprite *sprite, int *argc, const char ***argv) { - /* Read the arguments and create this sprite, the sprite buffer has already - * been allocated. This reads the input PNGs one by one in linear format, + /* Read the arguments and create this sprite. The sprite buffer has already + * been allocated. This reads the input PNGs one by one in linear format, * composes them onto the sprite buffer (the code in the function above) * then saves the result, converting it on the fly to PNG RGBA 8-bit format. */ @@ -226,8 +226,8 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv) 0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/)) { - /* This is the place were the Porter-Duff 'Over' operator - * needs to be done by this code. In fact any image + /* This is the place where the Porter-Duff 'Over' operator + * needs to be done by this code. In fact, any image * processing required can be done here; the data is in * the correct format (linear, 16-bit) and source and * destination are in memory. @@ -270,7 +270,7 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv) } } - /* All the sprite operations have completed successfully, save the RGBA + /* All the sprite operations have completed successfully. Save the RGBA * buffer as a PNG using the simplified write API. */ sprite->file = tmpfile(); @@ -291,7 +291,7 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv) if (png_image_write_to_stdio(&save, sprite->file, 1/*convert_to_8_bit*/, sprite->buffer, 0/*row_stride*/, NULL/*colormap*/)) { - /* Success, the buffer is no longer needed: */ + /* Success; the buffer is no longer needed: */ free(sprite->buffer); sprite->buffer = NULL; return 1; /* ok */ @@ -313,7 +313,7 @@ static int add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite, int *argc, const char ***argv) { - /* Given a --add argument naming this sprite perform the operations listed + /* Given a --add argument naming this sprite, perform the operations listed * in the following arguments. The arguments are expected to have the form * (x,y), which is just an offset at which to add the sprite to the * output. @@ -423,14 +423,14 @@ simpleover_process(png_imagep output, png_bytep out_buf, int argc, if (sprites[nsprites].name[0] == 0) sprintf(sprites[nsprites].name, "sprite-%d", nsprites+1); - /* Allocate a buffer for the sprite, calculate the buffer + /* Allocate a buffer for the sprite and calculate the buffer * size: */ buf_size = sizeof (png_uint_16 [4]); buf_size *= sprites[nsprites].width; buf_size *= sprites[nsprites].height; - /* This can overflow a (size_t), check for this: */ + /* This can overflow a (size_t); check for this: */ tmp = buf_size; tmp /= sprites[nsprites].width; tmp /= sprites[nsprites].height; @@ -488,7 +488,7 @@ simpleover_process(png_imagep output, png_bytep out_buf, int argc, if (strcmp(sprites[isprite].name, name) == 0) { if (!add_sprite(output, out_buf, sprites+isprite, &argc, &argv)) - goto out; /* error in addspite */ + goto out; /* error in addsprite */ break; } @@ -553,7 +553,7 @@ int main(int argc, const char **argv) if (buffer != NULL) { - png_color background = {0, 0xff, 0}; /* green (aka "lime") */ + png_color background = {0, 0xff, 0}; /* fully saturated green */ if (png_image_finish_read(&image, &background, buffer, 0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */)) @@ -619,7 +619,7 @@ int main(int argc, const char **argv) "simpleover: usage: simpleover background.png [output.png]\n" " Output 'background.png' as a 24-bit RGB PNG file in 'output.png'\n" " or, if not given, stdout. 'background.png' will be composited\n" - " on green.\n" + " on fully saturated green.\n" "\n" " Optionally, before output, process additional PNG files:\n" "\n"