Allow arbitrary text rotation onscreen (bug #33118) * gl-render.{h,cc} (opengl-renderer::draw_texture_image): New private method with code extracted from draw_image. (opengl-renderer::render_text (uint8NDArray ...)): New method to prepare text rendering and finally call draw_texture_image. Let the existing render_text(std::string,...) call this one after preparing the pixels array using text2pixels. (opengl-renderer::set_ortho_coordinates): New method to setup orthogonal transform. (opengl-renderer::restore_previous_coordinates): New method to restore previous transform. (opengl-renderer::draw_text): Handle clipping manually for the text as well. (opengl_texture::create): Add new case for uint8 RGBA image data. * graphics.{in.h,cc} (text::properties::get_extent_matrix): Add a bool argument "rotated" that defaults to "false". Re-compute the extent matrix if necessary. (text::properties::get_extent): Make use of get_extent_matrix. (text::properties::update_text_extent): Always call text2pixels with 0 degrees rotation. * __print_parse_opts__.m: By default, also use the opengl renderer for raster images that include rotated text.

--- a/libinterp/corefcn/gl-render.h	Fri Mar 12 19:12:04 2021 +0100
+++ b/libinterp/corefcn/gl-render.h	Fri Mar 12 20:56:19 2021 +0100
@@ -183,8 +183,15 @@
               | (z > zmax ? 1 : 0) << 5
               | (is_nan_or_inf (x, y, z) ? 0 : 1) << 6);
     }
+    
+    void render_text (uint8NDArray pixels, Matrix bbox,
+                      double x, double y, double z, double rotation);
+    
+    void set_normal (int bfl_mode, const NDArray& n, int j, int i);
 
-    void set_normal (int bfl_mode, const NDArray& n, int j, int i);
+    void set_ortho_coordinates (void);
+
+    void restore_previous_coordinates (void);
 
     double points_to_pixels (const double val) const;
 
@@ -204,6 +211,9 @@
     void draw_all_lights (const base_properties& props,
                           std::list<graphics_object>& obj_list);
 
+    void draw_texture_image (const octave_value cdata,
+                             Matrix x, Matrix y, bool ortho = false);
+
   protected:
 
     opengl_functions& m_glfcns;