Add pdf_layer configuration API.

Add API to:

 * allow enumeration of layer configs (OCCDs) within PDF files.

 * allow selection of layer configs.

 * allow enumeration of the "UI" (or "Human readable") form of layer
   configs.

 * allow selection/toggling of entries in the UI.

3 files changed, 122 insertions, 14 deletions

diff --git a/include/mupdf/pdf/document.h b/include/mupdf/pdf/document.h
index 5b9632ff..4cb4c819 100644
--- a/include/mupdf/pdf/document.h
+++ b/include/mupdf/pdf/document.h
@@ -119,20 +119,125 @@ int pdf_lookup_metadata(fz_context *ctx, pdf_document *doc, const char *key, cha
 
 fz_outline *pdf_load_outline(fz_context *ctx, pdf_document *doc);
 
-typedef struct pdf_ocg_entry_s pdf_ocg_entry;
+/*
+	pdf_count_layer_configs: Get the number of layer
+	configurations defined in this document.
+
+	doc: The document in question.
+*/
+int pdf_count_layer_configs(fz_context *ctx, pdf_document *doc);
 
-struct pdf_ocg_entry_s
+typedef struct
 {
-	int num;
-	int state;
-};
+	const char *name;
+	const char *creator;
+} pdf_layer_config;
+
+/*
+	pdf_layer_config_info: Fetch the name (and
+	optionally creator) of the given layer config.
+
+	doc: The document in question.
+
+	config_num: A value in the 0..n-1 range, where n is the
+	value returned from pdf_count_layer_configs.
+
+	info: Pointer to structure to fill in. Pointers within
+	this structure may be set to NULL if no information is
+	available.
+*/
+void pdf_layer_config_info(fz_context *ctx, pdf_document *doc, int config_num, pdf_layer_config *info);
+
+/*
+	pdf_select_layer_config: Set the current configuration.
+	This updates the visibility of the optional content groups
+	within the document.
+
+	doc: The document in question.
+
+	config_num: A value in the 0..n-1 range, where n is the
+	value returned from pdf_count_layer_configs.
+*/
+void pdf_select_layer_config(fz_context *ctx, pdf_document *doc, int config_num);
+
+/*
+	pdf_count_layer_config_ui: Returns the number of entries in the
+	'UI' for this layer configuration.
+
+	doc: The document in question.
+*/
+int pdf_count_layer_config_ui(fz_context *ctx, pdf_document *doc);
+
+/*
+	pdf_select_layer_ui: Select a checkbox/radiobox
+	within the 'UI' for this layer configuration.
+
+	Selecting a UI entry that is a radiobox may disable
+	other UI entries.
+
+	doc: The document in question.
 
-struct pdf_ocg_descriptor_s
+	ui: A value in the 0..m-1 range, where m is the value
+	returned by pdf_count_layer_config_ui.
+*/
+void pdf_select_layer_config_ui(fz_context *ctx, pdf_document *doc, int ui);
+
+/*
+	pdf_deselect_layer_ui: Select a checkbox/radiobox
+	within the 'UI' for this layer configuration.
+
+	doc: The document in question.
+
+	ui: A value in the 0..m-1 range, where m is the value
+	returned by pdf_count_layer_config_ui.
+*/
+void pdf_deselect_layer_config_ui(fz_context *ctx, pdf_document *doc, int ui);
+
+/*
+	pdf_toggle_layer_config_ui: Toggle a checkbox/radiobox
+	within the 'UI' for this layer configuration.
+
+	Toggling a UI entry that is a radiobox may disable
+	other UI entries.
+
+	doc: The document in question.
+
+	ui: A value in the 0..m-1 range, where m is the value
+	returned by pdf_count_layer_config_ui.
+*/
+void pdf_toggle_layer_config_ui(fz_context *ctx, pdf_document *doc, int ui);
+
+typedef enum
 {
-	int len;
-	pdf_ocg_entry *ocgs;
-	pdf_obj *intent;
-};
+	PDF_LAYER_UI_LABEL = 0,
+	PDF_LAYER_UI_CHECKBOX = 1,
+	PDF_LAYER_UI_RADIOBOX = 2
+} pdf_layer_config_ui_type;
+
+typedef struct
+{
+	const char *text;
+	int depth;
+	pdf_layer_config_ui_type type;
+	int selected;
+	int locked;
+} pdf_layer_config_ui;
+
+/*
+	pdf_layer_config_ui_info: Get the info for a given
+	entry in the layer config ui.
+
+	doc: The document in question.
+
+	ui: A value in the 0..m-1 range, where m is the value
+	returned by pdf_count_layer_config_ui.
+
+	info: Pointer to a structure to fill in with information
+	about the requested ui entry.
+*/
+void pdf_layer_config_ui_info(fz_context *ctx, pdf_document *doc, int ui, pdf_layer_config_ui *info);
+
+int pdf_is_hidden_ocg(fz_context *ctx, pdf_ocg_descriptor *desc, pdf_obj *rdb, const char *usage, pdf_obj *ocg);
 
 /*
 	pdf_update_page: update a page for the sake of changes caused by a call
diff --git a/include/mupdf/pdf/interpret.h b/include/mupdf/pdf/interpret.h
index 07460221..b7b85fff 100644
--- a/include/mupdf/pdf/interpret.h
+++ b/include/mupdf/pdf/interpret.h
@@ -127,7 +127,7 @@ struct pdf_processor_s
 	void (*op_END)(fz_context *ctx, pdf_processor *proc);
 
 	/* interpreter state that persists across content streams */
-	const char *event;
+	const char *usage;
 	int hidden;
 };
 
@@ -155,7 +155,7 @@ struct pdf_csi_s
 };
 
 /* Functions to set up pdf_process structures */
-pdf_processor *pdf_new_run_processor(fz_context *ctx, fz_device *dev, const fz_matrix *ctm, const char *event, pdf_gstate *gstate, int nested);
+pdf_processor *pdf_new_run_processor(fz_context *ctx, fz_device *dev, const fz_matrix *ctm, const char *usage, pdf_gstate *gstate, int nested);
 pdf_processor *pdf_new_buffer_processor(fz_context *ctx, fz_buffer *buffer, int ahxencode);
 pdf_processor *pdf_new_filter_processor(fz_context *ctx, pdf_processor *chain, pdf_document *doc, pdf_obj *old_res, pdf_obj *new_res);
 
diff --git a/include/mupdf/pdf/page.h b/include/mupdf/pdf/page.h
index a5a60be8..407fcc09 100644
--- a/include/mupdf/pdf/page.h
+++ b/include/mupdf/pdf/page.h
@@ -65,7 +65,7 @@ fz_rect *pdf_bound_page(fz_context *ctx, pdf_page *page, fz_rect *);
 void pdf_run_page(fz_context *ctx, pdf_page *page, fz_device *dev, const fz_matrix *ctm, fz_cookie *cookie);
 
 /*
-	pdf_run_page: Interpret a loaded page and render it on a device.
+	pdf_run_page_with_usage: Interpret a loaded page and render it on a device.
 
 	page: A page loaded by pdf_load_page.
 
@@ -74,10 +74,13 @@ void pdf_run_page(fz_context *ctx, pdf_page *page, fz_device *dev, const fz_matr
 	ctm: A transformation matrix applied to the objects on the page,
 	e.g. to scale or rotate the page contents as desired.
 
+	usage: The 'usage' for displaying the file (typically
+	'View', 'Print' or 'Export'). NULL means 'View'.
+
 	cookie: A pointer to an optional fz_cookie structure that can be used
 	to track progress, collect errors etc.
 */
-void pdf_run_page_with_usage(fz_context *ctx, pdf_document *doc, pdf_page *page, fz_device *dev, const fz_matrix *ctm, char *event, fz_cookie *cookie);
+void pdf_run_page_with_usage(fz_context *ctx, pdf_document *doc, pdf_page *page, fz_device *dev, const fz_matrix *ctm, const char *usage, fz_cookie *cookie);
 
 /*
 	pdf_run_page_contents: Interpret a loaded page and render it on a device.