[Textbox] Add placeholder.

Fixes: #1020

doc/rofi-theme.5

@@ -1043,28 +1043,32 @@ The offset of the window to the anchor point, allowing you to push the window le
 .SS textbox:
 .RS
 .IP \(bu 2
-\fBbackground\-color\fP:       color
+\fBbackground\-color\fP:  color
 .IP \(bu 2
-\fBborder\-color\fP:     the color used for the border around the widget.
+\fBborder\-color\fP:      the color used for the border around the widget.
 .IP \(bu 2
-\fBfont\fP:             the font used by this textbox (string).
+\fBfont\fP:              the font used by this textbox (string).
 .IP \(bu 2
-\fBstr\fP:              the string to display by this textbox (string).
+\fBstr\fP:               the string to display by this textbox (string).
 .IP \(bu 2
-\fBvertical\-align\fP:   vertical alignment of the text (\fB\fC0\fR top, \fB\fC1\fR bottom).
+\fBvertical\-align\fP:    vertical alignment of the text (\fB\fC0\fR top, \fB\fC1\fR bottom).
 .IP \(bu 2
-\fBhorizontal\-align\fP: horizontal alignment of the text (\fB\fC0\fR left, \fB\fC1\fR right).
+\fBhorizontal\-align\fP:  horizontal alignment of the text (\fB\fC0\fR left, \fB\fC1\fR right).
 .IP \(bu 2
-\fBtext\-color\fP:       the text color to use.
+\fBtext\-color\fP:        the text color to use.
 .IP \(bu 2
-\fBhighlight\fP:        text style {color}.
+\fBhighlight\fP:         text style {color}.
 color is optional, multiple highlight styles can be added like: bold underline italic #000000;
 .IP \(bu 2
-\fBwidth\fP:            override the desired width for the textbox.
+\fBwidth\fP:             override the desired width for the textbox.
 .IP \(bu 2
-\fBcontent\fP:          Set the displayed text (String).
+\fBcontent\fP:           Set the displayed text (String).
 .IP \(bu 2
-\fBblink\fP:            Enable/Disable blinking on an input textbox (Boolean).
+\fBplaceholder\fP:       Set the displayed text (String) when nothing is entered.
+.IP \(bu 2
+\fBplaceholder\-color\fP: Color of the placeholder text.
+.IP \(bu 2
+\fBblink\fP:             Enable/Disable blinking on an input textbox (Boolean).
 
 .RE
 

doc/rofi-theme.5.markdown

@@ -639,18 +639,20 @@ The following properties are currently supported:
 
 ### textbox:
 
-* **background-color**:       color
+* **background-color**:  color
-* **border-color**:     the color used for the border around the widget.
+* **border-color**:      the color used for the border around the widget.
-* **font**:             the font used by this textbox (string).
+* **font**:              the font used by this textbox (string).
-* **str**:              the string to display by this textbox (string).
+* **str**:               the string to display by this textbox (string).
-* **vertical-align**:   vertical alignment of the text (`0` top, `1` bottom).
+* **vertical-align**:    vertical alignment of the text (`0` top, `1` bottom).
-* **horizontal-align**: horizontal alignment of the text (`0` left, `1` right).
+* **horizontal-align**:  horizontal alignment of the text (`0` left, `1` right).
-* **text-color**:       the text color to use.
+* **text-color**:        the text color to use.
-* **highlight**:        text style {color}.
+* **highlight**:         text style {color}.
     color is optional, multiple highlight styles can be added like: bold underline italic #000000;
-* **width**:            override the desired width for the textbox.
+* **width**:             override the desired width for the textbox.
-* **content**:          Set the displayed text (String). 
+* **content**:           Set the displayed text (String).
-* **blink**:            Enable/Disable blinking on an input textbox (Boolean).
+* **placeholder**:       Set the displayed text (String) when nothing is entered.
+* **placeholder-color**: Color of the placeholder text.
+* **blink**:             Enable/Disable blinking on an input textbox (Boolean).
 
 ### listview:
 * **columns**:         integer

include/widgets/textbox.h

@@ -53,6 +53,8 @@ typedef struct
     unsigned long    flags;
     short            cursor;
     char             *text;
+    const char       *placeholder;
+    int              show_placeholder;
     PangoLayout      *layout;
     int              tbft;
     int              markup;

source/widgets/textbox.c

@@ -192,6 +192,10 @@ textbox* textbox_create ( widget *parent, WidgetType type, const char *name, Tex
     if ( !txt ){
         txt = rofi_theme_get_string ( WIDGET  ( tb ), "content", text );
     }
+    const char *placeholder = rofi_theme_get_string ( WIDGET(tb), "placeholder", NULL);
+    if ( placeholder){
+        tb->placeholder = placeholder;
+    }
     textbox_text ( tb, txt ? txt : "" );
     textbox_cursor_end ( tb );
 
@@ -264,6 +268,13 @@ void textbox_font ( textbox *tb, TextBoxFontType tbft )
 static void __textbox_update_pango_text ( textbox *tb )
 {
     pango_layout_set_attributes ( tb->layout, NULL );
+    if ( tb->placeholder && (tb->text == NULL || tb->text[0] == 0) )
+    {
+        tb->show_placeholder = TRUE;
+        pango_layout_set_text ( tb->layout, tb->placeholder, -1 );
+        return;
+    }
+    tb->show_placeholder = FALSE;
     if ( ( tb->flags & TB_PASSWORD ) == TB_PASSWORD ) {
         size_t l = g_utf8_strlen ( tb->text, -1 );
         char   string [l + 1];
@@ -430,6 +441,9 @@ static void textbox_draw ( widget *wid, cairo_t *draw )
     cairo_set_operator ( draw, CAIRO_OPERATOR_OVER );
     cairo_set_source_rgb ( draw, 0.0, 0.0, 0.0 );
     rofi_theme_get_color ( WIDGET ( tb ), "text-color", draw );
+    if ( tb->show_placeholder ) {
+        rofi_theme_get_color ( WIDGET ( tb ), "placeholder-color", draw );
+    }
     // draw the cursor
     if ( tb->flags & TB_EDITABLE && tb->blink ) {
         // We want to place the cursor based on the text shown.