resize.c: add pipi_crop() and the --crop flag.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@3415 92316355-f0b4-4df1-b90c-862c8a59935f

pipi/context.c

@@ -54,6 +54,7 @@ pipi_command_t const *pipi_get_command_list(void)
 
         { "gamma", 1 },
         { "scale", 1 },
+        { "crop", 1 },
         { "geometry", 1 },
         { "tile", 1 },
         { "dither", 1 },
@@ -365,6 +366,29 @@ int pipi_command(pipi_context_t *ctx, char const *cmd, ...)
         pipi_free(src);
         ctx->images[ctx->nimages - 1] = dst;
     }
+    else if(!strcmp(cmd, "crop"))
+    {
+        pipi_image_t *tmp;
+        char const *arg;
+        va_list ap;
+        int w, h, x = 0, y = 0;
+        int ret;
+
+        if(ctx->nimages < 1)
+            return -1;
+
+        va_start(ap, cmd);
+        arg = va_arg(ap, char const *);
+        va_end(ap);
+
+        ret = sscanf(arg, "%dx%d+%d+%d", &w, &h, &x, &y);
+        if(ret < 2)
+            return -1;
+
+        tmp = ctx->images[ctx->nimages - 1];
+        ctx->images[ctx->nimages - 1] = pipi_crop(tmp, w, h, x, y);
+        pipi_free(tmp);
+    }
     else if(!strcmp(cmd, "brightness"))
     {
         pipi_image_t *src, *dst;

pipi/pipi.h

@@ -157,6 +157,7 @@ __extern double pipi_measure_msd(pipi_image_t *, pipi_image_t *);
 __extern double pipi_measure_rmsd(pipi_image_t *, pipi_image_t *);
 
 __extern pipi_image_t *pipi_resize(pipi_image_t *, int, int);
+__extern pipi_image_t *pipi_crop(pipi_image_t *, int, int, int, int);
 
 __extern pipi_image_t *pipi_render_random(int, int);
 __extern pipi_image_t *pipi_render_bayer(int, int);

pipi/resize.c

@@ -123,3 +123,45 @@ pipi_image_t *pipi_resize(pipi_image_t *src, int w, int h)
     return dst;
 }
 
+pipi_image_t *pipi_crop(pipi_image_t *src, int w, int h, int dx, int dy)
+{
+    float *srcdata, *dstdata;
+    pipi_image_t *dst;
+    pipi_pixels_t *srcp, *dstp;
+    int y, off, len;
+
+    srcp = pipi_get_pixels(src, PIPI_PIXELS_RGBA_F32);
+    srcdata = (float *)srcp->pixels;
+
+    dst = pipi_new(w, h);
+    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
+    dstdata = (float *)dstp->pixels;
+
+    off = dx;
+    len = w;
+
+    if(dx < 0)
+    {
+        len += dx;
+        dx = 0;
+    }
+
+    if(dx + len > srcp->w)
+        len = srcp->w - dx;
+
+    if(len > 0)
+    {
+        for(y = 0; y < h; y++)
+        {
+            if(y + dy < 0 || y + dy >= srcp->h)
+                continue;
+
+            memcpy(dstdata + y * w * 4,
+                   srcdata + ((y + dy) * srcp->w + dx) * 4,
+                   len * 4 * sizeof(float));
+        }
+    }
+
+    return dst;
+}
+