Render text using Pango framework

Adds options to configure font face, size, and color for text output.

Signed-off-by: Artem Senichev <[email protected]>

.github/workflows/ci.yml

@@ -4,15 +4,16 @@ on: [push]
 jobs:
   build:
 
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
 
     steps:
     - name: Install dependencies
       run: >
           sudo apt install --no-install-recommends --yes
           build-essential meson pkg-config wayland-protocols
           libwayland-dev libcairo-dev libjson-c-dev libxkbcommon-dev
-          libgif-dev libjpeg-dev librsvg2-dev libwebp-dev
+          libpango1.0-dev libpangocairo-1.0-0
+          libavif-dev libgif-dev libjpeg-dev librsvg2-dev libwebp-dev
 
     - name: Check out source code
       uses: actions/[email protected]

extra/swayimgrc

@@ -20,6 +20,12 @@ background = grid
 # Show image info: format, size, EXIF, and current scale (yes/no)
 info = no
 
+# Font used to show image info
+font = monospace 10
+
+# Text color
+color = b4b4b4
+
 # Window class/app_id (default is autogenerated swayimg_XXXX)
 #app_id = swayimg
 

extra/swayimgrc.5

@@ -32,6 +32,8 @@ Empty lines and comments are ignored.
 .IP "\fBfullscreen\fR: start in full screen mode, possible values are \fIyes\fR or \fIno\fR;"
 .IP "\fBbackground\fR: background mode or color, possible values are \fIgrid\fR or RGB hex color (e.g. \fI1a2b3c\fR);"
 .IP "\fBinfo\fR: show image meta information: format, size, EXIF, and current scale, possible values are \fIyes\fR or \fIno\fR;"
+.IP "\fBfont\fR: font name and size used to render image info text in pango format;"
+.IP "\fBcolor\fR: color used to render text, RGB hex format (e.g. \fI1a2b3c\fR);"
 .IP "\fBapp_id\fR: set a constant window class/app_id, setting this may break the window layout;"
 .IP "\fBrules\fR: enable or disable adding Sway rules (window position management), possible values are \fIyes\fR or \fIno\fR."
 .\" example file
@@ -42,6 +44,7 @@ scale = fit
 fullscreen = no
 background = 1a2b3c
 info = yes
+font = monospace 10
 .EE
 .\" related man pages
 .SH SEE ALSO

meson.build

@@ -25,19 +25,21 @@ version = get_option('version')
 # mandatory dependencies
 wlcln = dependency('wayland-client')
 cairo = dependency('cairo')
-json  = dependency('json-c')
-xkb   = dependency('xkbcommon')
-rt    = cc.find_library('rt')
+json = dependency('json-c')
+xkb = dependency('xkbcommon')
+pango = dependency('pango')
+pangocairo = dependency('pangocairo')
+rt = cc.find_library('rt')
 # optional dependencies: file formats support
-avif  = dependency('libavif', required: get_option('avif'))
-gif   = cc.find_library('gif', required: get_option('gif'))
-jpeg  = dependency('libjpeg', required: get_option('jpeg'))
-png   = dependency('libpng', required: get_option('png'))
-rsvg  = dependency('librsvg-2.0', version: '>=2.46', required: get_option('svg'))
-webp  = dependency('libwebp', required: get_option('webp'))
+avif = dependency('libavif', required: get_option('avif'))
+gif = cc.find_library('gif', required: get_option('gif'))
+jpeg = dependency('libjpeg', required: get_option('jpeg'))
+png = dependency('libpng', required: get_option('png'))
+rsvg = dependency('librsvg-2.0', version: '>=2.46', required: get_option('svg'))
+webp = dependency('libwebp', required: get_option('webp'))
 # optional dependencies: other features
-exif  = dependency('libexif', required: get_option('exif'))
-bash  = dependency('bash-completion', required: get_option('bash'))
+exif = dependency('libexif', required: get_option('exif'))
+bash = dependency('bash-completion', required: get_option('bash'))
 # Arch specific: https://bugs.archlinux.org/task/73931
 jxl_feature = get_option('jxl')
 jxl = dependency('libjxl', required: false)
@@ -117,6 +119,7 @@ sources = [
   'src/image.c',
   'src/main.c',
   'src/sway.c',
+  'src/text.c',
   'src/viewer.c',
   'src/window.c',
   'src/formats/bmp.c',
@@ -160,6 +163,8 @@ executable(
     jpeg,
     json,
     jxl,
+    pango,
+    pangocairo,
     png,
     rsvg,
     rt,

src/canvas.c

@@ -9,13 +9,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-// Text render parameters
-#define FONT_FAMILY  "monospace"
-#define FONT_SIZE    16
-#define LINE_SPACING 2
-#define TEXT_COLOR   0xb2b2b2
-#define TEXT_SHADOW  0x101010
-
 // Background grid parameters
 #define GRID_STEP   10
 #define GRID_COLOR1 0x333333
@@ -146,39 +139,6 @@ void draw_grid(const canvas_t* canvas, cairo_surface_t* image, cairo_t* cairo)
     cairo_surface_mark_dirty(wnd_surface);
 }
 
-void draw_text(cairo_t* cairo, int x, int y, const char* text)
-{
-    // set font
-    cairo_font_face_t* font = cairo_toy_font_face_create(
-        FONT_FAMILY, CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
-    cairo_set_font_face(cairo, font);
-    cairo_set_font_size(cairo, FONT_SIZE);
-
-    // shadow
-    cairo_set_source_rgb(cairo, RGB_RED(TEXT_SHADOW), RGB_GREEN(TEXT_SHADOW),
-                         RGB_BLUE(TEXT_SHADOW));
-    cairo_move_to(cairo, x + 1, y + 1 + FONT_SIZE);
-    cairo_show_text(cairo, text);
-
-    // normal text
-    cairo_set_source_rgb(cairo, RGB_RED(TEXT_COLOR), RGB_GREEN(TEXT_COLOR),
-                         RGB_BLUE(TEXT_COLOR));
-    cairo_move_to(cairo, x, y + FONT_SIZE);
-    cairo_show_text(cairo, text);
-
-    cairo_set_font_face(cairo, NULL);
-    cairo_font_face_destroy(font);
-}
-
-void draw_lines(cairo_t* cairo, int x, int y, const char** lines)
-{
-    while (*lines) {
-        draw_text(cairo, x, y, *lines);
-        ++lines;
-        y += FONT_SIZE + LINE_SPACING;
-    }
-}
-
 bool move_viewpoint(canvas_t* canvas, cairo_surface_t* image, move_t direction)
 {
     const int img_w = canvas->scale * cairo_image_surface_get_width(image);

src/canvas.h

@@ -88,24 +88,6 @@ void draw_image(const canvas_t* canvas, cairo_surface_t* image, cairo_t* cairo);
  */
 void draw_grid(const canvas_t* canvas, cairo_surface_t* image, cairo_t* cairo);
 
-/**
- * Draw text line.
- * @param[in] cairo paint context
- * @param[in] x left offset
- * @param[in] y top offset
- * @param[in] text text to draw
- */
-void draw_text(cairo_t* cairo, int x, int y, const char* text);
-
-/**
- * Draw multiline text.
- * @param[in] cairo paint context
- * @param[in] x left offset
- * @param[in] y top offset
- * @param[in] lines array of strings, last line must be NULL
- */
-void draw_lines(cairo_t* cairo, int x, int y, const char** lines);
-
 /**
  * Move view point.
  * @param[in] canvas canvas context

src/config.c

@@ -16,6 +16,11 @@
 /** Max length of window class/app_id name */
 #define APP_ID_MAX 32
 
+/** Default font name/size */
+#define FONT_FACE "monospace 10"
+/** Default text color. */
+#define TEXT_COLOR 0xb4b4b4
+
 /** Config file location. */
 typedef struct {
     const char* prefix;  ///< Environment variable name
@@ -86,6 +91,44 @@ static bool set_boolean(const char* text, bool* value)
     return rc;
 }
 
+/**
+ * Convert text value to RGV color.
+ * @param[in] text text to convert
+ * @param[out] value target variable
+ * @return false if value has invalid format
+ */
+static bool set_color(const char* text, uint32_t* value)
+{
+    const unsigned long rgb = strtoul(text, NULL, 16);
+    if (rgb > 0x00ffffff || errno == ERANGE || (rgb == 0 && errno == EINVAL)) {
+        return false;
+    }
+    *value = rgb;
+    return true;
+}
+
+/**
+ * Set (replace) string in config parameter.
+ * @param[in] src source string
+ * @param[out] dst destination buffer
+ * @return false if not enough memory
+ */
+static bool set_string(const char* src, char** dst)
+{
+    const size_t len = strlen(src) + 1 /*last null*/;
+    char* ptr = malloc(len);
+    if (!ptr) {
+        fprintf(stderr, "Not enough memory\n");
+        return false;
+    }
+    memcpy(ptr, src, len);
+
+    free(*dst);
+    *dst = ptr;
+
+    return true;
+}
+
 /**
  * Apply property to configuration.
  * @param[out] cfg target configuration instance
@@ -104,6 +147,10 @@ static bool apply_conf(config_t* cfg, const char* key, const char* value)
         return set_background_config(cfg, value);
     } else if (strcmp(key, "info") == 0) {
         return set_boolean(value, &cfg->show_info);
+    } else if (strcmp(key, "font") == 0) {
+        return set_font_config(cfg, value);
+    } else if (strcmp(key, "color") == 0) {
+        return set_color(value, &cfg->font_color);
     } else if (strcmp(key, "app_id") == 0) {
         return set_appid_config(cfg, value);
     } else if (strcmp(key, "rules") == 0) {
@@ -130,6 +177,8 @@ static config_t* default_config(void)
     cfg->scale = scale_fit_or100;
     cfg->background = BACKGROUND_GRID;
     cfg->sway_rules = true;
+    set_font_config(cfg, FONT_FACE);
+    cfg->font_color = TEXT_COLOR;
 
     // create unique application id
     if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
@@ -228,6 +277,7 @@ config_t* init_config(void)
 void free_config(config_t* cfg)
 {
     if (cfg) {
+        free((void*)cfg->font_face);
         free((void*)cfg->app_id);
         free(cfg);
     }
@@ -273,21 +323,13 @@ bool set_scale_config(config_t* cfg, const char* scale)
 
 bool set_background_config(config_t* cfg, const char* background)
 {
-    uint32_t bkg;
-
     if (strcmp(background, "grid") == 0) {
-        bkg = BACKGROUND_GRID;
-    } else {
-        bkg = strtoul(background, NULL, 16);
-        if (bkg > 0x00ffffff || errno == ERANGE ||
-            (bkg == 0 && errno == EINVAL)) {
-            fprintf(stderr, "Invalid background: %s\n", background);
-            fprintf(stderr, "Expected 'grid' or RGB hex value.\n");
-            return false;
-        }
+        cfg->background = BACKGROUND_GRID;
+    } else if (!set_color(background, &cfg->background)) {
+        fprintf(stderr, "Invalid background: %s\n", background);
+        fprintf(stderr, "Expected 'grid' or RGB hex value.\n");
+        return false;
     }
-
-    cfg->background = bkg;
     return true;
 }
 
@@ -325,28 +367,22 @@ bool set_geometry_config(config_t* cfg, const char* geometry)
 
 bool set_appid_config(config_t* cfg, const char* app_id)
 {
-    char* ptr;
-    size_t len;
-
-    len = app_id ? strlen(app_id) : 0;
+    const size_t len = app_id ? strlen(app_id) : 0;
     if (len == 0 || len > APP_ID_MAX) {
         fprintf(stderr, "Invalid class/app_id: %s\n", app_id);
         fprintf(stderr, "Expected non-empty string up to %d chars.\n",
                 APP_ID_MAX);
         return false;
     }
+    return set_string(app_id, (char**)&cfg->app_id);
+}
 
-    ++len; // add last null
-
-    ptr = malloc(len);
-    if (!ptr) {
-        fprintf(stderr, "Not enough memory\n");
+bool set_font_config(config_t* cfg, const char* font)
+{
+    const size_t len = font ? strlen(font) : 0;
+    if (len == 0) {
+        fprintf(stderr, "Invalid font description: %s\n", font);
         return false;
     }
-    memcpy(ptr, app_id, len);
-
-    free((void*)cfg->app_id);
-    cfg->app_id = ptr;
-
-    return true;
+    return set_string(font, (char**)&cfg->font_face);
 }

src/config.h

@@ -7,13 +7,15 @@
 
 /** App configuration. */
 typedef struct {
-    scale_t scale;       ///< Initial scale
-    rect_t window;       ///< Window geometry
-    uint32_t background; ///< Background mode/color
-    bool fullscreen;     ///< Full screen mode
-    bool show_info;      ///< Show image info
-    const char* app_id;  ///< Window class/app_id name
-    bool sway_rules;     ///< Enable/disable Sway rules
+    scale_t scale;         ///< Initial scale
+    rect_t window;         ///< Window geometry
+    uint32_t background;   ///< Background mode/color
+    bool fullscreen;       ///< Full screen mode
+    bool show_info;        ///< Show image info
+    const char* font_face; ///< Font name and size (pango format)
+    uint32_t font_color;   ///< Font color
+    const char* app_id;    ///< Window class/app_id name
+    bool sway_rules;       ///< Enable/disable Sway rules
 } config_t;
 
 /**
@@ -66,3 +68,11 @@ bool set_geometry_config(config_t* cfg, const char* geometry);
  * @return false if value format is invalid
  */
 bool set_appid_config(config_t* cfg, const char* app_id);
+
+/**
+ * Set font name and size.
+ * @param[out] cfg target configuration instance
+ * @param[in] font font name and size in pango format
+ * @return false if value format is invalid
+ */
+bool set_font_config(config_t* cfg, const char* font);

src/exif.c

@@ -38,7 +38,7 @@ static void add_meta(image_t* img, ExifData* exif, ExifTag tag,
     if (entry) {
         exif_entry_get_value(entry, value, sizeof(value));
         if (*value) {
-            add_image_meta(img, name, value);
+            add_image_info(img, name, value);
         }
     }
 }
@@ -133,7 +133,7 @@ static void read_location(image_t* img, ExifData* exif)
         if (read_coordinate(exif, EXIF_TAG_GPS_LONGITUDE,
                             EXIF_TAG_GPS_LONGITUDE_REF, location + pos,
                             sizeof(location) - pos)) {
-            add_image_meta(img, "Location", location);
+            add_image_info(img, "Location", location);
         }
     }
 }