From: Hans de Goede <hdegoede@redhat.com>
Date: Thu, 19 Sep 2019 14:05:17 +0000 (+0200)
Subject: label: Properly deal with pixel-buffers with non-upright device_rotation
X-Git-Tag: 0.9.5~39^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7ef8b7edbfae8ca96655b8263c2cc2f2392ecdfa;p=thirdparty%2Fplymouth.git

label: Properly deal with pixel-buffers with non-upright device_rotation

Fix the label plugin rendering garbled (wrong pitch) top to bottom text,
instead of proper left to right text when the pixel-buffer has a
device-rotation of rotate-clockwise or rotate-counter-clockwise.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1753418
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---

diff --git a/src/plugins/controls/label/plugin.c b/src/plugins/controls/label/plugin.c
index b552981c..f1b687a6 100644
--- a/src/plugins/controls/label/plugin.c
+++ b/src/plugins/controls/label/plugin.c
@@ -96,27 +96,58 @@ destroy_control (ply_label_plugin_control_t *label)
 
 static cairo_t *
 get_cairo_context_for_pixel_buffer (ply_label_plugin_control_t *label,
-                                    ply_pixel_buffer_t         *pixel_buffer)
+                                    ply_pixel_buffer_t         *pixel_buffer,
+                                    long                       *center_x,
+                                    long                       *center_y)
 {
         cairo_surface_t *cairo_surface;
         cairo_t *cairo_context;
         unsigned char *data;
-        ply_rectangle_t size;
+        unsigned long width, height;
         uint32_t scale;
+        ply_pixel_buffer_rotation_t rotation;
 
         data = (unsigned char *) ply_pixel_buffer_get_argb32_data (pixel_buffer);
-        ply_pixel_buffer_get_size (pixel_buffer, &size);
+        width = ply_pixel_buffer_get_width (pixel_buffer);
+        height = ply_pixel_buffer_get_height (pixel_buffer);
         scale = ply_pixel_buffer_get_device_scale (pixel_buffer);
+        rotation = ply_pixel_buffer_get_device_rotation (pixel_buffer);
+
+        *center_x = width / 2;
+        *center_y = height / 2;
+
+        if (rotation == PLY_PIXEL_BUFFER_ROTATE_CLOCKWISE ||
+            rotation == PLY_PIXEL_BUFFER_ROTATE_COUNTER_CLOCKWISE) {
+                unsigned long tmp = width;
+                width = height;
+                height = tmp;
+        }
 
         cairo_surface = cairo_image_surface_create_for_data (data,
                                                              CAIRO_FORMAT_ARGB32,
-                                                             size.width * scale,
-                                                             size.height * scale,
-                                                             size.width * scale * 4);
+                                                             width * scale,
+                                                             height * scale,
+                                                             width * scale * 4);
         cairo_surface_set_device_scale (cairo_surface, scale, scale);
         cairo_context = cairo_create (cairo_surface);
         cairo_surface_destroy (cairo_surface);
 
+        /* Rotate around the center */
+        cairo_translate (cairo_context, width / 2, height / 2);
+        switch (rotation) {
+        case PLY_PIXEL_BUFFER_ROTATE_UPRIGHT:
+                break;
+        case PLY_PIXEL_BUFFER_ROTATE_UPSIDE_DOWN:
+                cairo_rotate (cairo_context, M_PI);
+                break;
+        case PLY_PIXEL_BUFFER_ROTATE_CLOCKWISE:
+                cairo_rotate (cairo_context, 0.5 * M_PI);
+                break;
+        case PLY_PIXEL_BUFFER_ROTATE_COUNTER_CLOCKWISE:
+                cairo_rotate (cairo_context, -0.5 * M_PI);
+                break;
+        }
+
         return cairo_context;
 }
 
@@ -202,13 +233,15 @@ draw_control (ply_label_plugin_control_t *label,
 {
         cairo_t *cairo_context;
         PangoLayout *pango_layout;
+        long center_x;
+        long center_y;
         int text_width;
         int text_height;
 
         if (label->is_hidden)
                 return;
 
-        cairo_context = get_cairo_context_for_pixel_buffer (label, pixel_buffer);
+        cairo_context = get_cairo_context_for_pixel_buffer (label, pixel_buffer, &center_x, &center_y);
 
         pango_layout = init_pango_text_layout (cairo_context, label->text, label->fontdesc, label->alignment, label->width);
 
@@ -216,11 +249,11 @@ draw_control (ply_label_plugin_control_t *label,
         label->area.width = (long) ((double) text_width / PANGO_SCALE);
         label->area.height = (long) ((double) text_height / PANGO_SCALE);
 
-        cairo_rectangle (cairo_context, x, y, width, height);
+        cairo_rectangle (cairo_context, x - center_x, y - center_y, width, height);
         cairo_clip (cairo_context);
         cairo_move_to (cairo_context,
-                       label->area.x,
-                       label->area.y);
+                       label->area.x - center_x,
+                       label->area.y - center_y);
         cairo_set_source_rgba (cairo_context,
                                label->red,
                                label->green,