Add lots of consts.

In general, we should use 'const fz_blah' in device calls whenever
the callee should not alter the fz_blah.

Push this through. This shows up various places where we fz_keep
and fz_drop these const things.

I've updated the fz_keep and fz_drops with appropriate casts
to remove the consts. We may need to do the union dance to avoid
the consts for some compilers, but will only do that if required.

I think this is nicer overall, even allowing for the const<->no const
problems.

12 files changed, 87 insertions, 88 deletions

diff --git a/include/mupdf/fitz/colorspace.h b/include/mupdf/fitz/colorspace.h
index b1b82999..0839e0eb 100644
--- a/include/mupdf/fitz/colorspace.h
+++ b/include/mupdf/fitz/colorspace.h
@@ -74,19 +74,19 @@ struct fz_colorspace_s
 	unsigned int size;
 	char name[16];
 	int n;
-	void (*to_rgb)(fz_context *ctx, fz_colorspace *, const float *src, float *rgb);
-	void (*from_rgb)(fz_context *ctx, fz_colorspace *, const float *rgb, float *dst);
-	void (*free_data)(fz_context *Ctx, fz_colorspace *);
+	void (*to_rgb)(fz_context *ctx, const fz_colorspace *, const float *src, float *rgb);
+	void (*from_rgb)(fz_context *ctx, const fz_colorspace *, const float *rgb, float *dst);
+	void (*free_data)(fz_context *Ctx, const fz_colorspace *);
 	void *data;
 };
 
 fz_colorspace *fz_new_colorspace(fz_context *ctx, char *name, int n);
 fz_colorspace *fz_new_indexed_colorspace(fz_context *ctx, fz_colorspace *base, int high, unsigned char *lookup);
-fz_colorspace *fz_keep_colorspace(fz_context *ctx, fz_colorspace *colorspace);
-void fz_drop_colorspace(fz_context *ctx, fz_colorspace *colorspace);
+fz_colorspace *fz_keep_colorspace(fz_context *ctx, const fz_colorspace *colorspace);
+void fz_drop_colorspace(fz_context *ctx, const fz_colorspace *colorspace);
 void fz_drop_colorspace_imp(fz_context *ctx, fz_storable *colorspace);
 
-void fz_convert_color(fz_context *ctx, fz_colorspace *dsts, float *dstv, fz_colorspace *srcs, const float *srcv);
+void fz_convert_color(fz_context *ctx, const fz_colorspace *dsts, float *dstv, const fz_colorspace *srcs, const float *srcv);
 
 void fz_new_colorspace_context(fz_context *ctx);
 fz_colorspace_context *fz_keep_colorspace_context(fz_context *ctx);
@@ -101,14 +101,14 @@ typedef struct fz_color_converter_s fz_color_converter;
 struct fz_color_converter_s
 {
 	void (*convert)(fz_context *, fz_color_converter *, float *, const float *);
-	fz_colorspace *ds;
-	fz_colorspace *ss;
+	const fz_colorspace *ds;
+	const fz_colorspace *ss;
 	void *opaque;
 };
 
-void fz_lookup_color_converter(fz_context *ctx, fz_color_converter *cc, fz_colorspace *ds, fz_colorspace *ss);
+void fz_lookup_color_converter(fz_context *ctx, fz_color_converter *cc, const fz_colorspace *ds, const fz_colorspace *ss);
 
-void fz_init_cached_color_converter(fz_context *ctx, fz_color_converter *cc, fz_colorspace *ds, fz_colorspace *ss);
+void fz_init_cached_color_converter(fz_context *ctx, fz_color_converter *cc, const fz_colorspace *ds, const fz_colorspace *ss);
 void fz_fin_cached_color_converter(fz_context *ctx, fz_color_converter *cc);
 
 #endif
diff --git a/include/mupdf/fitz/device.h b/include/mupdf/fitz/device.h
index 95c56c65..8c2c0219 100644
--- a/include/mupdf/fitz/device.h
+++ b/include/mupdf/fitz/device.h
@@ -106,25 +106,25 @@ struct fz_device_s
 	void (*begin_page)(fz_context *, fz_device *, const fz_rect *rect, const fz_matrix *ctm);
 	void (*end_page)(fz_context *, fz_device *);
 
-	void (*fill_path)(fz_context *, fz_device *, fz_path *, int even_odd, const fz_matrix *, fz_colorspace *, float *color, float alpha);
-	void (*stroke_path)(fz_context *, fz_device *, fz_path *, fz_stroke_state *, const fz_matrix *, fz_colorspace *, float *color, float alpha);
-	void (*clip_path)(fz_context *, fz_device *, fz_path *, const fz_rect *rect, int even_odd, const fz_matrix *);
-	void (*clip_stroke_path)(fz_context *, fz_device *, fz_path *, const fz_rect *rect, fz_stroke_state *, const fz_matrix *);
-
-	void (*fill_text)(fz_context *, fz_device *, fz_text *, const fz_matrix *, fz_colorspace *, float *color, float alpha);
-	void (*stroke_text)(fz_context *, fz_device *, fz_text *, fz_stroke_state *, const fz_matrix *, fz_colorspace *, float *color, float alpha);
-	void (*clip_text)(fz_context *, fz_device *, fz_text *, const fz_matrix *);
-	void (*clip_stroke_text)(fz_context *, fz_device *, fz_text *, fz_stroke_state *, const fz_matrix *);
-	void (*ignore_text)(fz_context *, fz_device *, fz_text *, const fz_matrix *);
-
-	void (*fill_shade)(fz_context *, fz_device *, fz_shade *shd, const fz_matrix *ctm, float alpha);
-	void (*fill_image)(fz_context *, fz_device *, fz_image *img, const fz_matrix *ctm, float alpha);
-	void (*fill_image_mask)(fz_context *, fz_device *, fz_image *img, const fz_matrix *ctm, fz_colorspace *, float *color, float alpha);
-	void (*clip_image_mask)(fz_context *, fz_device *, fz_image *img, const fz_rect *rect, const fz_matrix *ctm);
+	void (*fill_path)(fz_context *, fz_device *, const fz_path *, int even_odd, const fz_matrix *, const fz_colorspace *, const float *color, float alpha);
+	void (*stroke_path)(fz_context *, fz_device *, const fz_path *, const fz_stroke_state *, const fz_matrix *, const fz_colorspace *, const float *color, float alpha);
+	void (*clip_path)(fz_context *, fz_device *, const fz_path *, const fz_rect *rect, int even_odd, const fz_matrix *);
+	void (*clip_stroke_path)(fz_context *, fz_device *, const fz_path *, const fz_rect *rect, const fz_stroke_state *, const fz_matrix *);
+
+	void (*fill_text)(fz_context *, fz_device *, const fz_text *, const fz_matrix *, const fz_colorspace *, const float *color, float alpha);
+	void (*stroke_text)(fz_context *, fz_device *, const fz_text *, const fz_stroke_state *, const fz_matrix *, const fz_colorspace *, const float *color, float alpha);
+	void (*clip_text)(fz_context *, fz_device *, const fz_text *, const fz_matrix *);
+	void (*clip_stroke_text)(fz_context *, fz_device *, const fz_text *, const fz_stroke_state *, const fz_matrix *);
+	void (*ignore_text)(fz_context *, fz_device *, const fz_text *, const fz_matrix *);
+
+	void (*fill_shade)(fz_context *, fz_device *, const fz_shade *shd, const fz_matrix *ctm, float alpha);
+	void (*fill_image)(fz_context *, fz_device *, const fz_image *img, const fz_matrix *ctm, float alpha);
+	void (*fill_image_mask)(fz_context *, fz_device *, const fz_image *img, const fz_matrix *ctm, const fz_colorspace *, const float *color, float alpha);
+	void (*clip_image_mask)(fz_context *, fz_device *, const fz_image *img, const fz_rect *rect, const fz_matrix *ctm);
 
 	void (*pop_clip)(fz_context *, fz_device *);
 
-	void (*begin_mask)(fz_context *, fz_device *, const fz_rect *, int luminosity, fz_colorspace *, float *bc);
+	void (*begin_mask)(fz_context *, fz_device *, const fz_rect *, int luminosity, const fz_colorspace *, const float *bc);
 	void (*end_mask)(fz_context *, fz_device *);
 	void (*begin_group)(fz_context *, fz_device *, const fz_rect *, int isolated, int knockout, int blendmode, float alpha);
 	void (*end_group)(fz_context *, fz_device *);
@@ -146,21 +146,21 @@ struct fz_device_s
 
 void fz_begin_page(fz_context *ctx, fz_device *dev, const fz_rect *rect, const fz_matrix *ctm);
 void fz_end_page(fz_context *ctx, fz_device *dev);
-void fz_fill_path(fz_context *ctx, fz_device *dev, fz_path *path, int even_odd, const fz_matrix *ctm, fz_colorspace *colorspace, float *color, float alpha);
-void fz_stroke_path(fz_context *ctx, fz_device *dev, fz_path *path, fz_stroke_state *stroke, const fz_matrix *ctm, fz_colorspace *colorspace, float *color, float alpha);
-void fz_clip_path(fz_context *ctx, fz_device *dev, fz_path *path, const fz_rect *rect, int even_odd, const fz_matrix *ctm);
-void fz_clip_stroke_path(fz_context *ctx, fz_device *dev, fz_path *path, const fz_rect *rect, fz_stroke_state *stroke, const fz_matrix *ctm);
-void fz_fill_text(fz_context *ctx, fz_device *dev, fz_text *text, const fz_matrix *ctm, fz_colorspace *colorspace, float *color, float alpha);
-void fz_stroke_text(fz_context *ctx, fz_device *dev, fz_text *text, fz_stroke_state *stroke, const fz_matrix *ctm, fz_colorspace *colorspace, float *color, float alpha);
-void fz_clip_text(fz_context *ctx, fz_device *dev, fz_text *text, const fz_matrix *ctm);
-void fz_clip_stroke_text(fz_context *ctx, fz_device *dev, fz_text *text, fz_stroke_state *stroke, const fz_matrix *ctm);
-void fz_ignore_text(fz_context *ctx, fz_device *dev, fz_text *text, const fz_matrix *ctm);
+void fz_fill_path(fz_context *ctx, fz_device *dev, const fz_path *path, int even_odd, const fz_matrix *ctm, const fz_colorspace *colorspace, const float *color, float alpha);
+void fz_stroke_path(fz_context *ctx, fz_device *dev, const fz_path *path, const fz_stroke_state *stroke, const fz_matrix *ctm, const fz_colorspace *colorspace, const float *color, float alpha);
+void fz_clip_path(fz_context *ctx, fz_device *dev, const fz_path *path, const fz_rect *rect, int even_odd, const fz_matrix *ctm);
+void fz_clip_stroke_path(fz_context *ctx, fz_device *dev, const fz_path *path, const fz_rect *rect, const fz_stroke_state *stroke, const fz_matrix *ctm);
+void fz_fill_text(fz_context *ctx, fz_device *dev, const fz_text *text, const fz_matrix *ctm, const fz_colorspace *colorspace, const float *color, float alpha);
+void fz_stroke_text(fz_context *ctx, fz_device *dev, const fz_text *text, const fz_stroke_state *stroke, const fz_matrix *ctm, const fz_colorspace *colorspace, const float *color, float alpha);
+void fz_clip_text(fz_context *ctx, fz_device *dev, const fz_text *text, const fz_matrix *ctm);
+void fz_clip_stroke_text(fz_context *ctx, fz_device *dev, const fz_text *text, const fz_stroke_state *stroke, const fz_matrix *ctm);
+void fz_ignore_text(fz_context *ctx, fz_device *dev, const fz_text *text, const fz_matrix *ctm);
 void fz_pop_clip(fz_context *ctx, fz_device *dev);
-void fz_fill_shade(fz_context *ctx, fz_device *dev, fz_shade *shade, const fz_matrix *ctm, float alpha);
-void fz_fill_image(fz_context *ctx, fz_device *dev, fz_image *image, const fz_matrix *ctm, float alpha);
-void fz_fill_image_mask(fz_context *ctx, fz_device *dev, fz_image *image, const fz_matrix *ctm, fz_colorspace *colorspace, float *color, float alpha);
-void fz_clip_image_mask(fz_context *ctx, fz_device *dev, fz_image *image, const fz_rect *rect, const fz_matrix *ctm);
-void fz_begin_mask(fz_context *ctx, fz_device *dev, const fz_rect *area, int luminosity, fz_colorspace *colorspace, float *bc);
+void fz_fill_shade(fz_context *ctx, fz_device *dev, const fz_shade *shade, const fz_matrix *ctm, float alpha);
+void fz_fill_image(fz_context *ctx, fz_device *dev, const fz_image *image, const fz_matrix *ctm, float alpha);
+void fz_fill_image_mask(fz_context *ctx, fz_device *dev, const fz_image *image, const fz_matrix *ctm, const fz_colorspace *colorspace, const float *color, float alpha);
+void fz_clip_image_mask(fz_context *ctx, fz_device *dev, const fz_image *image, const fz_rect *rect, const fz_matrix *ctm);
+void fz_begin_mask(fz_context *ctx, fz_device *dev, const fz_rect *area, int luminosity, const fz_colorspace *colorspace, const float *bc);
 void fz_end_mask(fz_context *ctx, fz_device *dev);
 void fz_begin_group(fz_context *ctx, fz_device *dev, const fz_rect *area, int isolated, int knockout, int blendmode, float alpha);
 void fz_end_group(fz_context *ctx, fz_device *dev);
diff --git a/include/mupdf/fitz/font.h b/include/mupdf/fitz/font.h
index b6ea3362..eb3e1887 100644
--- a/include/mupdf/fitz/font.h
+++ b/include/mupdf/fitz/font.h
@@ -90,20 +90,20 @@ fz_font *fz_new_font_from_memory(fz_context *ctx, const char *name, unsigned cha
 fz_font *fz_new_font_from_buffer(fz_context *ctx, const char *name, fz_buffer *buffer, int index, int use_glyph_bbox);
 fz_font *fz_new_font_from_file(fz_context *ctx, const char *name, const char *path, int index, int use_glyph_bbox);
 
-fz_font *fz_keep_font(fz_context *ctx, fz_font *font);
-void fz_drop_font(fz_context *ctx, fz_font *font);
+fz_font *fz_keep_font(fz_context *ctx, const fz_font *font);
+void fz_drop_font(fz_context *ctx, const fz_font *font);
 
 void fz_set_font_bbox(fz_context *ctx, fz_font *font, float xmin, float ymin, float xmax, float ymax);
-fz_rect *fz_bound_glyph(fz_context *ctx, fz_font *font, int gid, const fz_matrix *trm, fz_rect *r);
-int fz_glyph_cacheable(fz_context *ctx, fz_font *font, int gid);
+fz_rect *fz_bound_glyph(fz_context *ctx, const fz_font *font, int gid, const fz_matrix *trm, fz_rect *r);
+int fz_glyph_cacheable(fz_context *ctx, const fz_font *font, int gid);
 
-void fz_run_t3_glyph(fz_context *ctx, fz_font *font, int gid, const fz_matrix *trm, struct fz_device_s *dev);
+void fz_run_t3_glyph(fz_context *ctx, const fz_font *font, int gid, const fz_matrix *trm, struct fz_device_s *dev);
 
 void fz_decouple_type3_font(fz_context *ctx, fz_font *font, void *t3doc);
 
-float fz_advance_glyph(fz_context *ctx, fz_font *font, int glyph);
-int fz_encode_character(fz_context *ctx, fz_font *font, int unicode);
+float fz_advance_glyph(fz_context *ctx, const fz_font *font, int glyph);
+int fz_encode_character(fz_context *ctx, const fz_font *font, int unicode);
 
-void fz_print_font(fz_context *ctx, fz_output *out, fz_font *font);
+void fz_print_font(fz_context *ctx, fz_output *out, const fz_font *font);
 
 #endif
diff --git a/include/mupdf/fitz/glyph-cache.h b/include/mupdf/fitz/glyph-cache.h
index 28fcf416..db9294fc 100644
--- a/include/mupdf/fitz/glyph-cache.h
+++ b/include/mupdf/fitz/glyph-cache.h
@@ -18,20 +18,20 @@ fz_glyph_cache *fz_keep_glyph_cache(fz_context *ctx);
 void fz_drop_glyph_cache_context(fz_context *ctx);
 void fz_purge_glyph_cache(fz_context *ctx);
 
-fz_path *fz_outline_ft_glyph(fz_context *ctx, fz_font *font, int gid, const fz_matrix *trm);
-fz_path *fz_outline_glyph(fz_context *ctx, fz_font *font, int gid, const fz_matrix *ctm);
-fz_glyph *fz_render_ft_glyph(fz_context *ctx, fz_font *font, int cid, const fz_matrix *trm, int aa);
-fz_pixmap *fz_render_ft_glyph_pixmap(fz_context *ctx, fz_font *font, int cid, const fz_matrix *trm, int aa);
-fz_glyph *fz_render_t3_glyph(fz_context *ctx, fz_font *font, int cid, const fz_matrix *trm, fz_colorspace *model, const fz_irect *scissor);
-fz_pixmap *fz_render_t3_glyph_pixmap(fz_context *ctx, fz_font *font, int cid, const fz_matrix *trm, fz_colorspace *model, const fz_irect *scissor);
-fz_glyph *fz_render_ft_stroked_glyph(fz_context *ctx, fz_font *font, int gid, const fz_matrix *trm, const fz_matrix *ctm, fz_stroke_state *state);
-fz_pixmap *fz_render_ft_stroked_glyph_pixmap(fz_context *ctx, fz_font *font, int gid, const fz_matrix *trm, const fz_matrix *ctm, fz_stroke_state *state);
-fz_glyph *fz_render_glyph(fz_context *ctx, fz_font*, int, fz_matrix *, fz_colorspace *model, const fz_irect *scissor);
-fz_pixmap *fz_render_glyph_pixmap(fz_context *ctx, fz_font*, int, fz_matrix *, fz_colorspace *model, const fz_irect *scissor);
-fz_glyph *fz_render_stroked_glyph(fz_context *ctx, fz_font*, int, fz_matrix *, const fz_matrix *, fz_stroke_state *stroke, const fz_irect *scissor);
-fz_pixmap *fz_render_stroked_glyph_pixmap(fz_context *ctx, fz_font*, int, fz_matrix *, const fz_matrix *, fz_stroke_state *stroke, const fz_irect *scissor);
-void fz_render_t3_glyph_direct(fz_context *ctx, fz_device *dev, fz_font *font, int gid, const fz_matrix *trm, void *gstate, int nestedDepth);
-void fz_prepare_t3_glyph(fz_context *ctx, fz_font *font, int gid, int nestedDepth);
+fz_path *fz_outline_ft_glyph(fz_context *ctx, const fz_font *font, int gid, const fz_matrix *trm);
+fz_path *fz_outline_glyph(fz_context *ctx, const fz_font *font, int gid, const fz_matrix *ctm);
+fz_glyph *fz_render_ft_glyph(fz_context *ctx, const fz_font *font, int cid, const fz_matrix *trm, int aa);
+fz_pixmap *fz_render_ft_glyph_pixmap(fz_context *ctx, const fz_font *font, int cid, const fz_matrix *trm, int aa);
+fz_glyph *fz_render_t3_glyph(fz_context *ctx, const fz_font *font, int cid, const fz_matrix *trm, fz_colorspace *model, const fz_irect *scissor);
+fz_pixmap *fz_render_t3_glyph_pixmap(fz_context *ctx, const fz_font *font, int cid, const fz_matrix *trm, fz_colorspace *model, const fz_irect *scissor);
+fz_glyph *fz_render_ft_stroked_glyph(fz_context *ctx, const fz_font *font, int gid, const fz_matrix *trm, const fz_matrix *ctm, const fz_stroke_state *state);
+fz_pixmap *fz_render_ft_stroked_glyph_pixmap(fz_context *ctx, const fz_font *font, int gid, const fz_matrix *trm, const fz_matrix *ctm, const fz_stroke_state *state);
+fz_glyph *fz_render_glyph(fz_context *ctx, const fz_font*, int, fz_matrix *, fz_colorspace *model, const fz_irect *scissor);
+fz_pixmap *fz_render_glyph_pixmap(fz_context *ctx, const fz_font*, int, fz_matrix *, fz_colorspace *model, const fz_irect *scissor);
+fz_glyph *fz_render_stroked_glyph(fz_context *ctx, const fz_font*, int, fz_matrix *, const fz_matrix *, const fz_stroke_state *stroke, const fz_irect *scissor);
+fz_pixmap *fz_render_stroked_glyph_pixmap(fz_context *ctx, const fz_font*, int, fz_matrix *, const fz_matrix *, const fz_stroke_state *stroke, const fz_irect *scissor);
+void fz_render_t3_glyph_direct(fz_context *ctx, fz_device *dev, const fz_font *font, int gid, const fz_matrix *trm, void *gstate, int nestedDepth);
+void fz_prepare_t3_glyph(fz_context *ctx, const fz_font *font, int gid, int nestedDepth);
 void fz_dump_glyph_cache_stats(fz_context *ctx);
 float fz_subpixel_adjust(fz_context *ctx, fz_matrix *ctm, fz_matrix *subpix_ctm, unsigned char *qe, unsigned char *qf);
 
diff --git a/include/mupdf/fitz/image.h b/include/mupdf/fitz/image.h
index 41b53475..080352da 100644
--- a/include/mupdf/fitz/image.h
+++ b/include/mupdf/fitz/image.h
@@ -34,14 +34,14 @@ typedef struct fz_image_s fz_image;
 
 	Returns a non NULL pixmap pointer. May throw exceptions.
 */
-fz_pixmap *fz_get_pixmap_from_image(fz_context *ctx, fz_image *image, int w, int h);
+fz_pixmap *fz_get_pixmap_from_image(fz_context *ctx, const fz_image *image, int w, int h);
 
 /*
 	fz_drop_image: Drop a reference to an image.
 
 	image: The image to drop a reference to.
 */
-void fz_drop_image(fz_context *ctx, fz_image *image);
+void fz_drop_image(fz_context *ctx, const fz_image *image);
 
 /*
 	fz_keep_image: Increment the reference count of an image.
@@ -50,15 +50,14 @@ void fz_drop_image(fz_context *ctx, fz_image *image);
 
 	Returns a pointer to the image.
 */
-fz_image *fz_keep_image(fz_context *ctx, fz_image *image);
+fz_image *fz_keep_image(fz_context *ctx, const fz_image *image);
 
 fz_image *fz_new_image(fz_context *ctx, int w, int h, int bpc, fz_colorspace *colorspace, int xres, int yres, int interpolate, int imagemask, float *decode, int *colorkey, fz_compressed_buffer *buffer, fz_image *mask);
 fz_image *fz_new_image_from_pixmap(fz_context *ctx, fz_pixmap *pixmap, fz_image *mask);
 fz_image *fz_new_image_from_data(fz_context *ctx, unsigned char *data, int len);
 fz_image *fz_new_image_from_buffer(fz_context *ctx, fz_buffer *buffer);
-fz_pixmap *fz_get_pixmap_from_image(fz_context *ctx, fz_image *image, int w, int h);
 void fz_drop_image_imp(fz_context *ctx, fz_storable *image);
-fz_pixmap *fz_decomp_image_from_stream(fz_context *ctx, fz_stream *stm, fz_image *image, int indexed, int l2factor);
+fz_pixmap *fz_decomp_image_from_stream(fz_context *ctx, fz_stream *stm, const fz_image *image, int indexed, int l2factor);
 fz_pixmap *fz_expand_indexed_pixmap(fz_context *ctx, fz_pixmap *src);
 
 struct fz_image_s
@@ -67,7 +66,7 @@ struct fz_image_s
 	int w, h, n, bpc;
 	fz_image *mask;
 	fz_colorspace *colorspace;
-	fz_pixmap *(*get_pixmap)(fz_context *, fz_image *, int w, int h, int *l2factor);
+	fz_pixmap *(*get_pixmap)(fz_context *, const fz_image *, int w, int h, int *l2factor);
 	int colorkey[FZ_MAX_COLORS * 2];
 	float decode[FZ_MAX_COLORS * 2];
 	int imagemask;
diff --git a/include/mupdf/fitz/output-png.h b/include/mupdf/fitz/output-png.h
index dd1ef465..7e0dfb87 100644
--- a/include/mupdf/fitz/output-png.h
+++ b/include/mupdf/fitz/output-png.h
@@ -29,7 +29,7 @@ void fz_write_png_trailer(fz_context *ctx, fz_output *out, fz_png_output_context
 /*
 	Create a new buffer containing the image/pixmap in PNG format.
 */
-fz_buffer *fz_new_buffer_from_image_as_png(fz_context *ctx, fz_image *image, int w, int h);
+fz_buffer *fz_new_buffer_from_image_as_png(fz_context *ctx, const fz_image *image, int w, int h);
 fz_buffer *fz_new_buffer_from_pixmap_as_png(fz_context *ctx, fz_pixmap *pixmap);
 
 #endif
diff --git a/include/mupdf/fitz/path.h b/include/mupdf/fitz/path.h
index ef308615..03c69849 100644
--- a/include/mupdf/fitz/path.h
+++ b/include/mupdf/fitz/path.h
@@ -80,15 +80,15 @@ void fz_closepath(fz_context*,fz_path*);
 
 void fz_transform_path(fz_context *ctx, fz_path *path, const fz_matrix *transform);
 
-fz_rect *fz_bound_path(fz_context *ctx, fz_path *path, const fz_stroke_state *stroke, const fz_matrix *ctm, fz_rect *r);
+fz_rect *fz_bound_path(fz_context *ctx, const fz_path *path, const fz_stroke_state *stroke, const fz_matrix *ctm, fz_rect *r);
 fz_rect *fz_adjust_rect_for_stroke(fz_context *ctx, fz_rect *r, const fz_stroke_state *stroke, const fz_matrix *ctm);
 
 extern const fz_stroke_state fz_default_stroke_state;
 
 fz_stroke_state *fz_new_stroke_state(fz_context *ctx);
 fz_stroke_state *fz_new_stroke_state_with_dash_len(fz_context *ctx, int len);
-fz_stroke_state *fz_keep_stroke_state(fz_context *ctx, fz_stroke_state *stroke);
-void fz_drop_stroke_state(fz_context *ctx, fz_stroke_state *stroke);
+fz_stroke_state *fz_keep_stroke_state(fz_context *ctx, const fz_stroke_state *stroke);
+void fz_drop_stroke_state(fz_context *ctx, const fz_stroke_state *stroke);
 fz_stroke_state *fz_unshare_stroke_state(fz_context *ctx, fz_stroke_state *shared);
 fz_stroke_state *fz_unshare_stroke_state_with_dash_len(fz_context *ctx, fz_stroke_state *shared, int len);
 fz_stroke_state *fz_clone_stroke_state(fz_context *ctx, fz_stroke_state *stroke);
diff --git a/include/mupdf/fitz/pixmap.h b/include/mupdf/fitz/pixmap.h
index 42a70c7b..be8f45ba 100644
--- a/include/mupdf/fitz/pixmap.h
+++ b/include/mupdf/fitz/pixmap.h
@@ -301,14 +301,14 @@ typedef struct fz_scale_cache_s fz_scale_cache;
 
 fz_scale_cache *fz_new_scale_cache(fz_context *ctx);
 void fz_drop_scale_cache(fz_context *ctx, fz_scale_cache *cache);
-fz_pixmap *fz_scale_pixmap_cached(fz_context *ctx, fz_pixmap *src, float x, float y, float w, float h, const fz_irect *clip, fz_scale_cache *cache_x, fz_scale_cache *cache_y);
+fz_pixmap *fz_scale_pixmap_cached(fz_context *ctx, const fz_pixmap *src, float x, float y, float w, float h, const fz_irect *clip, fz_scale_cache *cache_x, fz_scale_cache *cache_y);
 
 void fz_subsample_pixmap(fz_context *ctx, fz_pixmap *tile, int factor);
 
 fz_irect *fz_pixmap_bbox_no_ctx(fz_pixmap *src, fz_irect *bbox);
 
-void fz_decode_tile(fz_context *ctx, fz_pixmap *pix, float *decode);
-void fz_decode_indexed_tile(fz_context *ctx, fz_pixmap *pix, float *decode, int maxval);
+void fz_decode_tile(fz_context *ctx, fz_pixmap *pix, const float *decode);
+void fz_decode_indexed_tile(fz_context *ctx, fz_pixmap *pix, const float *decode, int maxval);
 void fz_unpack_tile(fz_context *ctx, fz_pixmap *dst, unsigned char * restrict src, int n, int depth, int stride, int scale);
 
 /*
diff --git a/include/mupdf/fitz/shade.h b/include/mupdf/fitz/shade.h
index 56adea5b..ada969cd 100644
--- a/include/mupdf/fitz/shade.h
+++ b/include/mupdf/fitz/shade.h
@@ -72,12 +72,12 @@ struct fz_shade_s
 	fz_compressed_buffer *buffer;
 };
 
-fz_shade *fz_keep_shade(fz_context *ctx, fz_shade *shade);
-void fz_drop_shade(fz_context *ctx, fz_shade *shade);
+fz_shade *fz_keep_shade(fz_context *ctx, const fz_shade *shade);
+void fz_drop_shade(fz_context *ctx, const fz_shade *shade);
 void fz_drop_shade_imp(fz_context *ctx, fz_storable *shade);
 
-fz_rect *fz_bound_shade(fz_context *ctx, fz_shade *shade, const fz_matrix *ctm, fz_rect *r);
-void fz_paint_shade(fz_context *ctx, fz_shade *shade, const fz_matrix *ctm, fz_pixmap *dest, const fz_irect *bbox);
+fz_rect *fz_bound_shade(fz_context *ctx, const fz_shade *shade, const fz_matrix *ctm, fz_rect *r);
+void fz_paint_shade(fz_context *ctx, const fz_shade *shade, const fz_matrix *ctm, fz_pixmap *dest, const fz_irect *bbox);
 
 /*
  *	Handy routine for processing mesh based shades
@@ -93,7 +93,7 @@ struct fz_vertex_s
 typedef void (fz_mesh_prepare_fn)(fz_context *ctx, void *arg, fz_vertex *v, const float *c);
 typedef void (fz_mesh_process_fn)(fz_context *ctx, void *arg, fz_vertex *av, fz_vertex *bv, fz_vertex *cv);
 
-void fz_process_mesh(fz_context *ctx, fz_shade *shade, const fz_matrix *ctm,
+void fz_process_mesh(fz_context *ctx, const fz_shade *shade, const fz_matrix *ctm,
 			fz_mesh_prepare_fn *prepare, fz_mesh_process_fn *process, void *process_arg);
 
 void fz_print_shade(fz_context *ctx, fz_output *out, fz_shade *shade);
diff --git a/include/mupdf/fitz/store.h b/include/mupdf/fitz/store.h
index 3b7b69ab..e98e2394 100644
--- a/include/mupdf/fitz/store.h
+++ b/include/mupdf/fitz/store.h
@@ -39,8 +39,8 @@ struct fz_storable_s {
 	S->drop = (DROP); \
 	} while (0)
 
-void *fz_keep_storable(fz_context *, fz_storable *);
-void fz_drop_storable(fz_context *, fz_storable *);
+void *fz_keep_storable(fz_context *, const fz_storable *);
+void fz_drop_storable(fz_context *, const fz_storable *);
 
 /*
 	The store can be seen as a dictionary that maps keys to fz_storable
@@ -73,7 +73,7 @@ struct fz_store_hash_s
 		} i;
 		struct
 		{
-			void *ptr;
+			const void *ptr;
 			int i;
 		} pi;
 		struct
diff --git a/include/mupdf/fitz/text.h b/include/mupdf/fitz/text.h
index 302678cd..090d372d 100644
--- a/include/mupdf/fitz/text.h
+++ b/include/mupdf/fitz/text.h
@@ -46,12 +46,12 @@ struct fz_text_s
 };
 
 fz_text *fz_new_text(fz_context *ctx);
-fz_text *fz_keep_text(fz_context *ctx, fz_text *text);
-void fz_drop_text(fz_context *ctx, fz_text *text);
+fz_text *fz_keep_text(fz_context *ctx, const fz_text *text);
+void fz_drop_text(fz_context *ctx, const fz_text *text);
 
 void fz_add_text(fz_context *ctx, fz_text *text, fz_font *font, int wmode, const fz_matrix *trm, int gid, int ucs);
-fz_rect *fz_bound_text(fz_context *ctx, fz_text *text, const fz_stroke_state *stroke, const fz_matrix *ctm, fz_rect *r);
+fz_rect *fz_bound_text(fz_context *ctx, const fz_text *text, const fz_stroke_state *stroke, const fz_matrix *ctm, fz_rect *r);
 
-fz_text *fz_clone_text(fz_context *ctx, fz_text *text);
+fz_text *fz_clone_text(fz_context *ctx, const fz_text *text);
 
 #endif
diff --git a/include/mupdf/pdf/resource.h b/include/mupdf/pdf/resource.h
index 868bd168..a97b9b84 100644
--- a/include/mupdf/pdf/resource.h
+++ b/include/mupdf/pdf/resource.h
@@ -15,7 +15,7 @@ void pdf_remove_item(fz_context *ctx, fz_store_drop_fn *drop, pdf_obj *key);
 fz_function *pdf_load_function(fz_context *ctx, pdf_document *doc, pdf_obj *ref, int in, int out);
 
 fz_colorspace *pdf_load_colorspace(fz_context *ctx, pdf_document *doc, pdf_obj *obj);
-int pdf_is_tint_colorspace(fz_context *ctx, fz_colorspace *cs);
+int pdf_is_tint_colorspace(fz_context *ctx, const fz_colorspace *cs);
 
 fz_shade *pdf_load_shading(fz_context *ctx, pdf_document *doc, pdf_obj *obj);