Use separate buffers for i3bar statusline for each workspace, track short and long renders separately, fixes #1824

i3bar/include/common.h

@@ -31,6 +31,14 @@ typedef enum {
     ALIGN_RIGHT
 } blockalign_t;
 
+/* This data structure describes the way a status block should be rendered. These
+ * variables are updated each time the statusline is re-rendered. */
+struct status_block_render_desc {
+    uint32_t width;
+    uint32_t x_offset;
+    uint32_t x_append;
+};
+
 /* This data structure represents one JSON dictionary, multiple of these make
  * up one status line. */
 struct status_block {
@@ -56,11 +64,9 @@ struct status_block {
     /* The amount of pixels necessary to render a separater after the block. */
     uint32_t sep_block_width;
 
-    /* The amount of pixels necessary to render this block. These variables are
+    /* Continuously-updated information on how to render this status block. */
-     * only temporarily used in refresh_statusline(). */
+    struct status_block_render_desc full_render;
-    uint32_t width;
+    struct status_block_render_desc short_render;
-    uint32_t x_offset;
-    uint32_t x_append;
 
     /* Optional */
     char *name;

i3bar/include/outputs.h

@@ -46,8 +46,14 @@ struct i3_output {
     int ws;       /* The number of the currently visible ws */
     rect rect;    /* The rect (relative to the root window) */
 
-    /* Off-screen buffer for preliminary rendering. */
+    /* Off-screen buffer for preliminary rendering of the bar. */
     surface_t buffer;
+    /* Off-screen buffer for pre-rendering the statusline, separated to make clipping easier. */
+    surface_t statusline_buffer;
+    /* How much of statusline_buffer's horizontal space was used on last statusline render. */
+    int statusline_width;
+    /* Whether statusline block short texts where used on last statusline render. */
+    bool statusline_short_text;
     /* The actual window on which we draw. */
     surface_t bar;
 

i3bar/src/ipc.c

@@ -63,7 +63,6 @@ void got_output_reply(char *reply) {
     DLOG("Parsing outputs JSON...\n");
     parse_outputs_json(reply);
     DLOG("Reconfiguring windows...\n");
-    realloc_sl_buffer();
     reconfig_windows(false);
 
     i3_output *o_walk;
@@ -175,7 +174,6 @@ void got_bar_config_update(char *event) {
     /* update fonts and colors */
     init_xcb_late(config.fontname);
     init_colors(&(config.colors));
-    realloc_sl_buffer();
 
     draw_bars(false);
 }

i3bar/src/outputs.c

@@ -144,10 +144,16 @@ static int outputs_start_map_cb(void *params_) {
     if (params->cur_key == NULL) {
         new_output = smalloc(sizeof(i3_output));
         new_output->name = NULL;
+        new_output->active = false;
+        new_output->primary = false;
+        new_output->visible = false;
         new_output->ws = 0,
+        new_output->statusline_width = 0;
+        new_output->statusline_short_text = false;
         memset(&new_output->rect, 0, sizeof(rect));
         memset(&new_output->bar, 0, sizeof(surface_t));
         memset(&new_output->buffer, 0, sizeof(surface_t));
+        memset(&new_output->statusline_buffer, 0, sizeof(surface_t));
 
         new_output->workspaces = smalloc(sizeof(struct ws_head));
         TAILQ_INIT(new_output->workspaces);

i3bar/src/xcb.c

@@ -74,11 +74,6 @@ int bar_height;
 int xkb_base;
 int mod_pressed = 0;
 
-/* Because the statusline is the same on all outputs, we have
- * global buffer to render it on */
-surface_t statusline_surface;
-uint32_t statusline_width;
-
 /* Event watchers, to interact with the user */
 ev_prepare *xcb_prep;
 ev_check *xcb_chk;
@@ -165,7 +160,7 @@ int get_tray_width(struct tc_head *trayclients) {
  * Draws a separator for the given block if necessary.
  *
  */
-static void draw_separator(uint32_t x, struct status_block *block) {
+static void draw_separator(i3_output *output, uint32_t x, struct status_block *block) {
     uint32_t sep_offset = get_sep_offset(block);
     if (TAILQ_NEXT(block, blocks) == NULL || sep_offset == 0)
         return;
@@ -173,7 +168,7 @@ static void draw_separator(uint32_t x, struct status_block *block) {
     uint32_t center_x = x - sep_offset;
     if (config.separator_symbol == NULL) {
         /* Draw a classic one pixel, vertical separator. */
-        draw_util_rectangle(&statusline_surface, colors.sep_fg,
+        draw_util_rectangle(&output->statusline_buffer, colors.sep_fg,
                             center_x,
                             logical_px(sep_voff_px),
                             logical_px(1),
@@ -181,119 +176,138 @@ static void draw_separator(uint32_t x, struct status_block *block) {
     } else {
         /* Draw a custom separator. */
         uint32_t separator_x = MAX(x - block->sep_block_width, center_x - separator_symbol_width / 2);
-        draw_util_text(config.separator_symbol, &statusline_surface, colors.sep_fg, colors.bar_bg,
+        draw_util_text(config.separator_symbol, &output->statusline_buffer, colors.sep_fg, colors.bar_bg,
                        separator_x, logical_px(ws_voff_px), x - separator_x);
     }
 }
 
-/*
+uint32_t predict_statusline_length(bool use_short_text) {
- * Redraws the statusline to the buffer
+    uint32_t width = 0;
- *
- */
-void refresh_statusline(bool use_short_text) {
     struct status_block *block;
 
-    uint32_t old_statusline_width = statusline_width;
-    statusline_width = 0;
-
-    /* Predict the text width of all blocks (in pixels). */
     TAILQ_FOREACH(block, &statusline_head, blocks) {
-        /* Try to use the shorter text if necessary and possible. */
+        i3String *text = block->full_text;
+        struct status_block_render_desc *render = &block->full_render;
         if (use_short_text && block->short_text != NULL) {
-            I3STRING_FREE(block->full_text);
+            text = block->short_text;
-            block->full_text = i3string_copy(block->short_text);
+            render = &block->short_render;
         }
 
-        if (i3string_get_num_bytes(block->full_text) == 0)
+        if (i3string_get_num_bytes(text) == 0)
             continue;
 
-        block->width = predict_text_width(block->full_text);
+        render->width = predict_text_width(text);
-        /* Add padding for the border if we have to draw it. */
         if (block->border)
-            block->width += logical_px(2);
+            render->width += logical_px(2);
 
         /* Compute offset and append for text aligment in min_width. */
-        if (block->min_width <= block->width) {
+        if (block->min_width <= render->width) {
-            block->x_offset = 0;
+            render->x_offset = 0;
-            block->x_append = 0;
+            render->x_append = 0;
         } else {
-            uint32_t padding_width = block->min_width - block->width;
+            uint32_t padding_width = block->min_width - render->width;
             switch (block->align) {
                 case ALIGN_LEFT:
-                    block->x_append = padding_width;
+                    render->x_append = padding_width;
                     break;
                 case ALIGN_RIGHT:
-                    block->x_offset = padding_width;
+                    render->x_offset = padding_width;
                     break;
                 case ALIGN_CENTER:
-                    block->x_offset = padding_width / 2;
+                    render->x_offset = padding_width / 2;
-                    block->x_append = padding_width / 2 + padding_width % 2;
+                    render->x_append = padding_width / 2 + padding_width % 2;
                     break;
             }
         }
 
+        width += render->width + render->x_offset + render->x_append;
+
         /* If this is not the last block, add some pixels for a separator. */
         if (TAILQ_NEXT(block, blocks) != NULL)
-            statusline_width += block->sep_block_width;
+            width += block->sep_block_width;
-
-        statusline_width += block->width + block->x_offset + block->x_append;
     }
 
-    /* If the statusline is bigger than our screen we need to make sure that
+    return width;
-     * the pixmap provides enough space, so re-allocate if the width grew */
+}
-    if (statusline_width > root_screen->width_in_pixels &&
-        statusline_width > old_statusline_width)
-        realloc_sl_buffer();
 
-    /* Clear the statusline pixmap. */
+/*
-    draw_util_clear_surface(&statusline_surface, colors.bar_bg);
+ * Redraws the statusline to the output's statusline_buffer
+ */
+void draw_statusline(i3_output *output, uint32_t clip_left, bool use_short_text) {
+    struct status_block *block;
 
-    /* Draw the text of each block. */
+    draw_util_clear_surface(&output->statusline_buffer, colors.bar_bg);
-    uint32_t x = 0;
+
+    /* Use unsigned integer wraparound to clip off the left side.
+     * For example, if clip_left is 75, then x will start at the very large
+     * number INT_MAX-75, which is way outside the surface dimensions. Drawing
+     * to that x position is a no-op which XCB and Cairo safely ignore. Once x moves
+     * up by 75 and goes past INT_MAX, it will wrap around again to 0, and we start
+     * actually rendering content to the surface. */
+    uint32_t x = 0 - clip_left;
+
+    /* Draw the text of each block */
     TAILQ_FOREACH(block, &statusline_head, blocks) {
-        if (i3string_get_num_bytes(block->full_text) == 0)
+        i3String *text = block->full_text;
+        struct status_block_render_desc *render = &block->full_render;
+        if (use_short_text && block->short_text != NULL) {
+            text = block->short_text;
+            render = &block->short_render;
+        }
+
+        if (i3string_get_num_bytes(text) == 0)
             continue;
 
-        color_t fg_color = (block->color ? draw_util_hex_to_color(block->color) : colors.bar_fg);
+        color_t fg_color;
-        int border_width = (block->border) ? logical_px(1) : 0;
+        if (block->urgent) {
-        if (block->border || block->background || block->urgent) {
-            if (block->urgent)
             fg_color = colors.urgent_ws_fg;
+        } else if (block->color) {
+            fg_color = draw_util_hex_to_color(block->color);
+        } else {
+            fg_color = colors.bar_fg;
+        }
 
+        color_t bg_color = colors.bar_bg;
+
+        int border_width = (block->border) ? logical_px(1) : 0;
+        int full_render_width = render->width + render->x_offset + render->x_append;
+        if (block->border || block->background || block->urgent) {
             /* Let's determine the colors first. */
             color_t border_color = colors.bar_bg;
-            color_t bg_color = colors.bar_bg;
             if (block->urgent) {
                 border_color = colors.urgent_ws_border;
                 bg_color = colors.urgent_ws_bg;
             } else {
                 if (block->border)
                     border_color = draw_util_hex_to_color(block->border);
-
                 if (block->background)
                     bg_color = draw_util_hex_to_color(block->background);
             }
 
             /* Draw the border. */
-            draw_util_rectangle(&statusline_surface, border_color,
+            draw_util_rectangle(&output->statusline_buffer, border_color,
                                 x, logical_px(1),
-                                block->width + block->x_offset + block->x_append,
+                                full_render_width,
                                 bar_height - logical_px(2));
 
             /* Draw the background. */
-            draw_util_rectangle(&statusline_surface, bg_color,
+            draw_util_rectangle(&output->statusline_buffer, bg_color,
                                 x + border_width,
                                 logical_px(1) + border_width,
-                                block->width + block->x_offset + block->x_append - 2 * border_width,
+                                full_render_width - 2 * border_width,
                                 bar_height - 2 * border_width - logical_px(2));
         }
 
-        draw_util_text(block->full_text, &statusline_surface, fg_color, colors.bar_bg,
+        draw_util_text(text, &output->statusline_buffer, fg_color, bg_color,
-                       x + block->x_offset + border_width, logical_px(ws_voff_px), block->width - 2 * border_width);
+                       x + render->x_offset + border_width, logical_px(ws_voff_px),
-        x += block->width + block->sep_block_width + block->x_offset + block->x_append;
+                       render->width - 2 * border_width);
+        x += full_render_width;
 
         /* If this is not the last block, draw a separator. */
-        draw_separator(x, block);
+        if (TAILQ_NEXT(block, blocks) != NULL) {
+            x += block->sep_block_width;
+            draw_separator(output, x, block);
+        }
     }
 }
 
@@ -426,7 +440,6 @@ void handle_button(xcb_button_press_event_t *event) {
     }
 
     int32_t x = event->event_x >= 0 ? event->event_x : 0;
-    int32_t original_x = x;
 
     DLOG("Got button %d\n", event->detail);
 
@@ -449,21 +462,28 @@ void handle_button(xcb_button_press_event_t *event) {
          * check if a status block has been clicked. */
         int tray_width = get_tray_width(walk->trayclients);
         int block_x = 0, last_block_x;
-        int offset = walk->rect.w - statusline_width - tray_width - logical_px(sb_hoff_px);
+        int offset = walk->rect.w - walk->statusline_width - tray_width - logical_px(sb_hoff_px);
+        int32_t statusline_x = x - offset;
 
-        x = original_x - offset;
+        if (statusline_x >= 0 && statusline_x < walk->statusline_width) {
-        if (x >= 0 && (size_t)x < statusline_width) {
             struct status_block *block;
             int sep_offset_remainder = 0;
 
             TAILQ_FOREACH(block, &statusline_head, blocks) {
-                if (i3string_get_num_bytes(block->full_text) == 0)
+                i3String *text = block->full_text;
+                struct status_block_render_desc *render = &block->full_render;
+                if (walk->statusline_short_text && block->short_text != NULL) {
+                    text = block->short_text;
+                    render = &block->short_render;
+                }
+
+                if (i3string_get_num_bytes(text) == 0)
                     continue;
 
                 last_block_x = block_x;
-                block_x += block->width + block->x_offset + block->x_append + get_sep_offset(block) + sep_offset_remainder;
+                block_x += render->width + render->x_offset + render->x_append + get_sep_offset(block) + sep_offset_remainder;
 
-                if (x <= block_x && x >= last_block_x) {
+                if (statusline_x <= block_x && statusline_x >= last_block_x) {
                     send_block_clicked(event->detail, block->name, block->instance, event->root_x, event->root_y);
                     return;
                 }
@@ -471,7 +491,6 @@ void handle_button(xcb_button_press_event_t *event) {
                 sep_offset_remainder = block->sep_block_width - get_sep_offset(block);
             }
         }
-        x = original_x;
     }
 
     /* If a custom command was specified for this mouse button, it overrides
@@ -1147,17 +1166,6 @@ char *init_xcb_early() {
     colormap = root_screen->default_colormap;
     visual_type = get_visualtype(root_screen);
 
-    /* We draw the statusline to a seperate pixmap, because it looks the same on all bars and
-     * this way, we can choose to crop it */
-    xcb_pixmap_t statusline_id = xcb_generate_id(xcb_connection);
-    xcb_void_cookie_t sl_pm_cookie = xcb_create_pixmap_checked(xcb_connection,
-                                                               depth,
-                                                               statusline_id,
-                                                               xcb_root,
-                                                               root_screen->width_in_pixels,
-                                                               root_screen->height_in_pixels);
-    draw_util_surface_init(&statusline_surface, statusline_id, root_screen->width_in_pixels, root_screen->height_in_pixels);
-
     /* The various watchers to communicate with xcb */
     xcb_io = smalloc(sizeof(ev_io));
     xcb_prep = smalloc(sizeof(ev_prepare));
@@ -1176,9 +1184,6 @@ char *init_xcb_early() {
 
     char *path = root_atom_contents("I3_SOCKET_PATH", xcb_connection, screen);
 
-    if (xcb_request_failed(sl_pm_cookie, "Could not allocate statusline buffer"))
-        exit(EXIT_FAILURE);
-
     return path;
 }
 
@@ -1510,29 +1515,6 @@ void destroy_window(i3_output *output) {
     output->bar.id = XCB_NONE;
 }
 
-/*
- * Reallocate the statusline buffer
- *
- */
-void realloc_sl_buffer(void) {
-    DLOG("Re-allocating statusline buffer, statusline_width = %d, root_screen->width_in_pixels = %d\n",
-         statusline_width, root_screen->width_in_pixels);
-    xcb_free_pixmap(xcb_connection, statusline_surface.id);
-    draw_util_surface_free(&statusline_surface);
-
-    xcb_pixmap_t statusline_id = xcb_generate_id(xcb_connection);
-    xcb_void_cookie_t sl_pm_cookie = xcb_create_pixmap_checked(xcb_connection,
-                                                               depth,
-                                                               statusline_id,
-                                                               xcb_root,
-                                                               MAX(root_screen->width_in_pixels, statusline_width),
-                                                               bar_height);
-    draw_util_surface_init(&statusline_surface, statusline_id, root_screen->width_in_pixels, root_screen->height_in_pixels);
-
-    if (xcb_request_failed(sl_pm_cookie, "Could not allocate statusline buffer"))
-        exit(EXIT_FAILURE);
-}
-
 /* Strut partial tells i3 where to reserve space for i3bar. This is determined
  * by the `position` bar config directive. */
 xcb_void_cookie_t config_strut_partial(i3_output *output) {
@@ -1600,6 +1582,7 @@ void reconfig_windows(bool redraw_bars) {
 
             xcb_window_t bar_id = xcb_generate_id(xcb_connection);
             xcb_pixmap_t buffer_id = xcb_generate_id(xcb_connection);
+            xcb_pixmap_t statusline_buffer_id = xcb_generate_id(xcb_connection);
             mask = XCB_CW_BACK_PIXEL | XCB_CW_BORDER_PIXEL | XCB_CW_OVERRIDE_REDIRECT | XCB_CW_EVENT_MASK | XCB_CW_COLORMAP;
 
             values[0] = colors.bar_bg.colorpixel;
@@ -1643,6 +1626,14 @@ void reconfig_windows(bool redraw_bars) {
                                                                     walk->rect.w,
                                                                     bar_height);
 
+            /* The double-buffer we use to render the statusline before copying to buffer */
+            xcb_void_cookie_t slpm_cookie = xcb_create_pixmap_checked(xcb_connection,
+                                                                      depth,
+                                                                      statusline_buffer_id,
+                                                                      bar_id,
+                                                                      walk->rect.w,
+                                                                      bar_height);
+
             /* Set the WM_CLASS and WM_NAME (we don't need UTF-8) atoms */
             xcb_void_cookie_t class_cookie;
             class_cookie = xcb_change_property(xcb_connection,
@@ -1680,6 +1671,7 @@ void reconfig_windows(bool redraw_bars) {
 
             draw_util_surface_init(&walk->bar, bar_id, walk->rect.w, bar_height);
             draw_util_surface_init(&walk->buffer, buffer_id, walk->rect.w, bar_height);
+            draw_util_surface_init(&walk->statusline_buffer, statusline_buffer_id, walk->rect.w, bar_height);
 
             xcb_void_cookie_t strut_cookie = config_strut_partial(walk);
 
@@ -1691,6 +1683,7 @@ void reconfig_windows(bool redraw_bars) {
 
             if (xcb_request_failed(win_cookie, "Could not create window") ||
                 xcb_request_failed(pm_cookie, "Could not create pixmap") ||
+                xcb_request_failed(slpm_cookie, "Could not create statusline pixmap") ||
                 xcb_request_failed(dock_cookie, "Could not set dock mode") ||
                 xcb_request_failed(class_cookie, "Could not set WM_CLASS") ||
                 xcb_request_failed(name_cookie, "Could not set WM_NAME") ||
@@ -1737,6 +1730,9 @@ void reconfig_windows(bool redraw_bars) {
             DLOG("Destroying buffer for output %s\n", walk->name);
             xcb_free_pixmap(xcb_connection, walk->buffer.id);
 
+            DLOG("Destroying statusline buffer for output %s\n", walk->name);
+            xcb_free_pixmap(xcb_connection, walk->statusline_buffer.id);
+
             DLOG("Reconfiguring window for output %s to %d,%d\n", walk->name, values[0], values[1]);
             xcb_void_cookie_t cfg_cookie = xcb_configure_window_checked(xcb_connection,
                                                                         walk->bar.id,
@@ -1759,10 +1755,20 @@ void reconfig_windows(bool redraw_bars) {
                                                                     walk->rect.w,
                                                                     bar_height);
 
+            DLOG("Recreating statusline buffer for output %s\n", walk->name);
+            xcb_void_cookie_t slpm_cookie = xcb_create_pixmap_checked(xcb_connection,
+                                                                      depth,
+                                                                      walk->statusline_buffer.id,
+                                                                      walk->bar.id,
+                                                                      walk->rect.w,
+                                                                      bar_height);
+
             draw_util_surface_free(&(walk->bar));
             draw_util_surface_free(&(walk->buffer));
+            draw_util_surface_free(&(walk->statusline_buffer));
             draw_util_surface_init(&(walk->bar), walk->bar.id, walk->rect.w, bar_height);
             draw_util_surface_init(&(walk->buffer), walk->buffer.id, walk->rect.w, bar_height);
+            draw_util_surface_init(&(walk->statusline_buffer), walk->statusline_buffer.id, walk->rect.w, bar_height);
 
             xcb_void_cookie_t map_cookie, umap_cookie;
             if (redraw_bars) {
@@ -1787,6 +1793,7 @@ void reconfig_windows(bool redraw_bars) {
             if (xcb_request_failed(cfg_cookie, "Could not reconfigure window") ||
                 xcb_request_failed(chg_cookie, "Could not change window") ||
                 xcb_request_failed(pm_cookie, "Could not create pixmap") ||
+                xcb_request_failed(slpm_cookie, "Could not create statusline pixmap") ||
                 xcb_request_failed(strut_cookie, "Could not set strut") ||
                 (redraw_bars && (xcb_request_failed(umap_cookie, "Could not unmap window") ||
                                  (config.hide_on_modifier == M_DOCK && xcb_request_failed(map_cookie, "Could not map window"))))) {
@@ -1802,14 +1809,14 @@ void reconfig_windows(bool redraw_bars) {
  */
 void draw_bars(bool unhide) {
     DLOG("Drawing bars...\n");
-    int workspace_width = 0;
-    /* Is the currently-rendered statusline using short_text items? */
-    bool rendered_statusline_is_short = false;
 
-    refresh_statusline(false);
+    uint32_t full_statusline_width = predict_statusline_length(false);
+    uint32_t short_statusline_width = predict_statusline_length(true);
 
     i3_output *outputs_walk;
     SLIST_FOREACH(outputs_walk, outputs, slist) {
+        int workspace_width = 0;
+
         if (!outputs_walk->active) {
             DLOG("Output %s inactive, skipping...\n", outputs_walk->name);
             continue;
@@ -1906,30 +1913,28 @@ void draw_bars(bool unhide) {
 
             int tray_width = get_tray_width(outputs_walk->trayclients);
             uint32_t max_statusline_width = outputs_walk->rect.w - workspace_width - tray_width - 2 * logical_px(sb_hoff_px);
+            uint32_t clip_left = 0;
+            uint32_t statusline_width = full_statusline_width;
+            bool use_short_text = false;
 
-            /* If the statusline is too long, try to use short texts. */
             if (statusline_width > max_statusline_width) {
-                /* If the currently rendered statusline is long, render a short status line */
+                statusline_width = short_statusline_width;
-                refresh_statusline(true);
+                use_short_text = true;
-                rendered_statusline_is_short = true;
+                if (statusline_width > max_statusline_width) {
-            } else if (rendered_statusline_is_short) {
+                    clip_left = statusline_width - max_statusline_width;
-                /* If the currently rendered statusline is short, render a long status line */
+                }
-                refresh_statusline(false);
-                rendered_statusline_is_short = false;
             }
 
-            /* Luckily we already prepared a seperate pixmap containing the rendered
+            int16_t visible_statusline_width = MIN(statusline_width, max_statusline_width);
-             * statusline, we just have to copy the relevant parts to the relevant
+            int x_dest = outputs_walk->rect.w - tray_width - logical_px(sb_hoff_px) - visible_statusline_width;
-             * position */
-            int visible_statusline_width = MIN(statusline_width, max_statusline_width);
-            int x_src = (int16_t)(statusline_width - visible_statusline_width);
-            int x_dest = (int16_t)(outputs_walk->rect.w - tray_width - logical_px(sb_hoff_px) - visible_statusline_width);
 
-            draw_util_copy_surface(&statusline_surface, &(outputs_walk->buffer), x_src, 0,
+            draw_statusline(outputs_walk, clip_left, use_short_text);
-                                   x_dest, 0, (int16_t)visible_statusline_width, (int16_t)bar_height);
+            draw_util_copy_surface(&outputs_walk->statusline_buffer, &outputs_walk->buffer, 0, 0,
+                                   x_dest, 0, visible_statusline_width, (int16_t)bar_height);
+
+            outputs_walk->statusline_width = statusline_width;
+            outputs_walk->statusline_short_text = use_short_text;
         }
-
-        workspace_width = 0;
     }
 
     /* Assure the bar is hidden/unhidden according to the specified hidden_state and mode */