Merge SVG support from mobilized Dillo fork

Uses the nanosvg library to add SVG support.

See: https://www.toomanyatoms.com/software/mobilized_dillo.html
Authored-By: dogma

1 files changed, 149 insertions, 0 deletions

diff --git a/src/svg.c b/src/svg.c
new file mode 100644
index 00000000..406cfab9
--- /dev/null
+++ b/src/svg.c
@@ -0,0 +1,149 @@
+#include <config.h>
+
+#ifdef ENABLE_SVG
+
+#include <stdlib.h> /* For abort() */
+
+#include "msg.h"
+#include "image.hh"
+#include "cache.h"
+#include "dicache.h"
+
+#define NANOSVG_ALL_COLOR_KEYWORDS
+#define NANOSVG_IMPLEMENTATION
+#include "nanosvg.h"
+#define NANOSVGRAST_IMPLEMENTATION
+#include "nanosvgrast.h"
+
+typedef struct {
+   DilloImage *Image;           /* Image meta data */
+   DilloUrl *url;               /* Primary Key for the dicache */
+   int version;                 /* Secondary Key for the dicache */
+   int bgcolor;                 /* Parent widget background color */
+} DilloSvg;
+
+/*
+ * Free up the resources for this image.
+ */
+static void Svg_free(DilloSvg *svg)
+{
+   _MSG("Svg_free: svg=%p\n", svg);
+
+   dFree(svg);
+}
+
+/*
+ * Finish the decoding process (and free the memory)
+ */
+static void Svg_close(DilloSvg *svg, CacheClient_t *Client)
+{
+   _MSG("Svg_close\n");
+   /* Let dicache know decoding is over */
+   a_Dicache_close(svg->url, svg->version, Client);
+   Svg_free(svg);
+}
+
+/*
+ * Receive and process new chunks of SVG image data
+ */
+static void Svg_write(DilloSvg *svg, void *Buf, uint_t BufSize)
+{
+   uint_t i, j, width, height;
+   static NSVGrasterizer *rasterizer = NULL;
+
+   if (!rasterizer)
+      rasterizer = nsvgCreateRasterizer();
+
+   dReturn_if_fail ( Buf != NULL && BufSize > 0 );
+   dReturn_if_fail (strstr(Buf, "</svg>"));
+
+   char *str = dStrndup(Buf, BufSize); /* 1. nsvg is said to modify the string. 2. it needs it null-terminated, and I don't remember right now whether Buf happens to be */
+
+   /* TODO: Use FLTK reported DPI value */
+   NSVGimage *nimg = nsvgParse(str, "px", 96);
+   dFree(str);
+
+   /* guess what? The height and width values that come back can be nonintegral */
+   width = ceil(nimg->width);
+   height = ceil(nimg->height);
+
+   if (width == 0 || height == 0 || width > IMAGE_MAX_AREA / height) {
+      MSG_WARN("Svg_write: suspicious image size request %u x %u\n", width, height);
+      nsvgDelete(nimg);
+      return;
+   }
+
+   const DilloImgType type = DILLO_IMG_TYPE_RGB;
+   const uint_t stride = width * 4;
+
+   a_Dicache_set_parms(svg->url, svg->version, svg->Image, width, height,
+                       type, 1 / 2.2);
+
+   /* is there any sort of gamma to deal with at all? Not aware of any. */
+
+   unsigned char *dest = dNew(unsigned char, height * stride);
+
+   nsvgRasterizeXY(rasterizer, nimg, 0, 0, 1, 1, dest, width, height, stride);
+
+       uint_t bg_blue  = (svg->bgcolor) & 0xFF;
+       uint_t bg_green = (svg->bgcolor>>8) & 0xFF;
+       uint_t bg_red   = (svg->bgcolor>>16) & 0xFF;
+
+   unsigned char *line = dNew(unsigned char, width * 3);
+   for (i = 0; i < height; i++) {
+      for (j = 0; j < width; j++) {
+         uchar_t r = dest[i * stride + 4 * j];
+         uchar_t g = dest[i * stride + 4 * j + 1];
+         uchar_t b = dest[i * stride + 4 * j + 2];
+         uchar_t alpha = dest[i * stride + 4 * j + 3];
+
+         if (i * stride + 4 * j + 3 >= height * stride) {
+            MSG_ERR("height %f i %d width %f j %d stride %d size %d here %d\n", nimg->height, i, nimg->width, j, stride, height * stride, i * stride + 4 * j + 3);
+         }
+
+         line[3 * j] = (r * alpha + (bg_red * (0xFF - alpha))) / 0xFF;
+         line[3 * j + 1] = (g * alpha + (bg_green * (0xFF - alpha))) / 0xFF;
+         line[3 * j + 2] = (b * alpha + (bg_blue * (0xFF - alpha))) / 0xFF;
+      }
+      a_Dicache_write(svg->url, svg->version, line, i);
+   }
+   dFree(dest);
+   dFree(line);
+   nsvgDelete(nimg);
+}
+
+void a_Svg_callback(int Op, void *data)
+{
+   if (Op == CA_Send) {
+      CacheClient_t *Client = data;
+      Svg_write(Client->CbData, Client->Buf, Client->BufSize);
+   } else if (Op == CA_Close) {
+      CacheClient_t *Client = data;
+      Svg_close(Client->CbData, Client);
+   } else if (Op == CA_Abort) {
+      Svg_free(data);
+   }
+}
+
+/*
+ * Create the image state data that must be kept between calls
+ */
+void *a_Svg_new(DilloImage *Image, DilloUrl *url, int version)
+{
+   DilloSvg *svg = dNew0(DilloSvg, 1);
+   _MSG("a_Svg_new: svg=%p\n", svg);
+
+   svg->Image = Image;
+   svg->url = url;
+   svg->version = version;
+   svg->bgcolor = Image->bg_color;
+
+   return svg;
+}
+
+#else /* ENABLE_SVG */
+
+void *a_Svg_new() { return 0; }
+void a_Svg_callback() { return; }
+
+#endif /* ENABLE_SVG */