render: Introduce render_pager to factor out code from drivers.

[pspp] / src / output / render.h

diff --git a/src/output/render.h b/src/output/render.h
index aa1980adf505f0680379a2f68b9adf2e2e21bc07..eed29e8512a74c7d9a87160054d58f1dff16dbdf 100644 (file)
--- a/src/output/render.h
+++ b/src/output/render.h
@@ -44,6 +44,19 @@ struct render_params
     int (*measure_cell_height) (void *aux, const struct table_cell *cell,
                                 int width);
 
+    /* Given that there is space measuring WIDTH by HEIGHT to render CELL,
+       where HEIGHT is insufficient to render the entire height of the cell,
+       returns the largest height less than HEIGHT at which it is appropriate
+       to break the cell.  For example, if breaking at the specified HEIGHT
+       would break in the middle of a line of text, the return value would be
+       just sufficiently less that the breakpoint would be between lines of
+       text.
+
+       Optional.  If NULL, the rendering engine assumes that all breakpoints
+       are acceptable. */
+    int (*adjust_break) (void *aux, const struct table_cell *cell,
+                         int width, int height);
+
     /* Draws a generalized intersection of lines in the rectangle whose
        top-left corner is (BB[TABLE_HORZ][0], BB[TABLE_VERT][0]) and whose
        bottom-right corner is (BB[TABLE_HORZ][1], BB[TABLE_VERT][1]).
@@ -88,7 +101,7 @@ struct render_params
 /* A "page" of content that is ready to be rendered.
 
    A page's size is not limited to the size passed in as part of render_params.
-   Use render_break (see below) to break a too-big render_page into smaller
+   Use render_pager (see below) to break a render_page into smaller
    render_pages that will fit in the available space. */
 struct render_page *render_page_create (const struct render_params *,
                                         const struct table *);
@@ -100,24 +113,15 @@ int render_page_get_size (const struct render_page *, enum table_axis);
 void render_page_draw (const struct render_page *);
 void render_page_draw_region (const struct render_page *,
                               int x, int y, int w, int h);
+
+int render_page_get_best_breakpoint (const struct render_page *, int height);
 \f
 /* An iterator for breaking render_pages into smaller chunks. */
-struct render_break
-  {
-    struct render_page *page;   /* Page being broken up. */
-    enum table_axis axis;       /* Axis along which 'page' is being broken. */
-    int z;                      /* Next cell along 'axis'. */
-    int pixel;                  /* Pixel offset within cell 'z' (usually 0). */
-    int hw;                     /* Width of headers of 'page' along 'axis'. */
-  };
 
-void render_break_init (struct render_break *, struct render_page *,
-                        enum table_axis);
-void render_break_init_empty (struct render_break *);
-void render_break_destroy (struct render_break *);
+struct render_pager *render_pager_create (struct render_page *);
+void render_pager_destroy (struct render_pager *);
 
-bool render_break_has_next (const struct render_break *);
-int render_break_next_size (const struct render_break *);
-struct render_page *render_break_next (struct render_break *, int size);
+bool render_pager_has_next (const struct render_pager *);
+struct render_page *render_pager_next (struct render_pager *, int height);
 
 #endif /* output/render.h */