Add support for GIF images.

docs/src/mainpage.dox

@@ -21,7 +21,7 @@ features such as:
 - Charts.
 - Data validation and drop down lists.
 - Conditional formatting.
-- Worksheet PNG/JPEG images.
+- Worksheet PNG/JPEG/GIF images.
 - Cell comments.
 - Support for adding Macros.
 - Memory optimization mode for writing large files.

include/xlsxwriter/common.h

@@ -317,15 +317,17 @@ enum lxw_custom_property_types {
     }
 
 #ifndef LXW_BIG_ENDIAN
+#define LXW_UINT16_HOST(n)    (n)
+#define LXW_UINT32_HOST(n)    (n)
+#define LXW_UINT16_NETWORK(n) ((((n) & 0x00FF) << 8) | (((n) & 0xFF00) >> 8))
 #define LXW_UINT32_NETWORK(n) ((((n) & 0xFF)       << 24) | \
                                (((n) & 0xFF00)     <<  8) | \
                                (((n) & 0xFF0000)   >>  8) | \
                                (((n) & 0xFF000000) >> 24))
-#define LXW_UINT16_NETWORK(n) ((((n) & 0x00FF) << 8) | (((n) & 0xFF00) >> 8))
-#define LXW_UINT32_HOST(n)    (n)
 #else
-#define LXW_UINT32_NETWORK(n) (n)
 #define LXW_UINT16_NETWORK(n) (n)
+#define LXW_UINT32_NETWORK(n) (n)
+#define LXW_UINT16_HOST(n)    ((((n) & 0x00FF) << 8) | (((n) & 0xFF00) >> 8))
 #define LXW_UINT32_HOST(n)    ((((n) & 0xFF)       << 24) | \
                                (((n) & 0xFF00)     <<  8) | \
                                (((n) & 0xFF0000)   >>  8) | \

include/xlsxwriter/drawing.h

@@ -27,7 +27,8 @@ enum image_types {
     LXW_IMAGE_UNKNOWN = 0,
     LXW_IMAGE_PNG,
     LXW_IMAGE_JPEG,
-    LXW_IMAGE_BMP
+    LXW_IMAGE_BMP,
+    LXW_IMAGE_GIF
 };
 
 /* Coordinates used in a drawing object. */

include/xlsxwriter/workbook.h

@@ -319,6 +319,7 @@ typedef struct lxw_workbook {
     uint8_t has_png;
     uint8_t has_jpeg;
     uint8_t has_bmp;
+    uint8_t has_gif;
     uint8_t has_vml;
     uint8_t has_comments;
     uint8_t has_metadata;

include/xlsxwriter/worksheet.h

@@ -2973,7 +2973,7 @@ lxw_error worksheet_set_column_pixels_opt(lxw_worksheet *worksheet,
  * @return A #lxw_error code.
  *
  * This function can be used to insert a image into a worksheet. The image can
- * be in PNG, JPEG or BMP format:
+ * be in PNG, JPEG, GIF or BMP format:
  *
  * @code
  *     worksheet_insert_image(worksheet, 2, 1, "logo.png");

libxlsxwriter.podspec

@@ -18,7 +18,7 @@ Pod::Spec.new do |s|
                             * Charts.
                             * Data validation and drop down lists.
                             * Conditional formatting.
-                            * Worksheet PNG/JPEG images.
+                            * Worksheet PNG/JPEG/GIF images.
                             * Cell comments.
                             * Support for adding Macros.
                             * Memory optimisation mode for writing large files.

src/packager.c

@@ -969,6 +969,9 @@ _write_content_types_file(lxw_packager *self)
     if (workbook->has_bmp)
         lxw_ct_add_default(content_types, "bmp", "image/bmp");
 
+    if (workbook->has_gif)
+        lxw_ct_add_default(content_types, "gif", "image/gif");
+
     if (workbook->vba_project)
         lxw_ct_add_default(content_types, "bin",
                            "application/vnd.ms-office.vbaProject");

src/workbook.c

@@ -1050,6 +1050,9 @@ _prepare_drawings(lxw_workbook *self)
             if (object_props->image_type == LXW_IMAGE_BMP)
                 self->has_bmp = LXW_TRUE;
 
+            if (object_props->image_type == LXW_IMAGE_GIF)
+                self->has_gif = LXW_TRUE;
+
             /* Check for duplicate images and only store the first instance. */
             if (object_props->md5) {
                 tmp_image_md5.md5 = object_props->md5;
@@ -1108,6 +1111,9 @@ _prepare_drawings(lxw_workbook *self)
             if (object_props->image_type == LXW_IMAGE_BMP)
                 self->has_bmp = LXW_TRUE;
 
+            if (object_props->image_type == LXW_IMAGE_GIF)
+                self->has_gif = LXW_TRUE;
+
             /* Check for duplicate images and only store the first instance. */
             if (object_props->md5) {
                 tmp_image_md5.md5 = object_props->md5;

src/worksheet.c

@@ -3403,6 +3403,55 @@ file_error:
     return LXW_ERROR_IMAGE_DIMENSIONS;
 }
 
+/*
+ * Extract width and height information from a GIF file.
+ */
+STATIC lxw_error
+_process_gif(lxw_object_properties *image_props)
+{
+    uint16_t width = 0;
+    uint16_t height = 0;
+    double x_dpi = 96;
+    double y_dpi = 96;
+    int fseek_err;
+
+    FILE *stream = image_props->stream;
+
+    /* Skip another 2 bytes to the start of the GIF height/width. */
+    fseek_err = fseek(stream, 2, SEEK_CUR);
+    if (fseek_err)
+        goto file_error;
+
+    if (fread(&width, sizeof(width), 1, stream) < 1)
+        width = 0;
+
+    if (fread(&height, sizeof(height), 1, stream) < 1)
+        height = 0;
+
+    /* Ensure that we read some valid data from the file. */
+    if (width == 0)
+        goto file_error;
+
+    height = LXW_UINT16_HOST(height);
+    width = LXW_UINT16_HOST(width);
+
+    /* Set the image metadata. */
+    image_props->image_type = LXW_IMAGE_GIF;
+    image_props->width = width;
+    image_props->height = height;
+    image_props->x_dpi = x_dpi;
+    image_props->y_dpi = y_dpi;
+    image_props->extension = lxw_strdup("gif");
+
+    return LXW_NO_ERROR;
+
+file_error:
+    LXW_WARN_FORMAT1("worksheet image insertion: "
+                     "no size data found in: %s.", image_props->filename);
+
+    return LXW_ERROR_IMAGE_DIMENSIONS;
+}
+
 /*
  * Extract information from the image file such as dimension, type, filename,
  * and extension.
@@ -3439,6 +3488,10 @@ _get_image_properties(lxw_object_properties *image_props)
         if (_process_bmp(image_props) != LXW_NO_ERROR)
             return LXW_ERROR_IMAGE_DIMENSIONS;
     }
+    else if (memcmp(signature, "GIF8", 4) == 0) {
+        if (_process_gif(image_props) != LXW_NO_ERROR)
+            return LXW_ERROR_IMAGE_DIMENSIONS;
+    }
     else {
         LXW_WARN_FORMAT1("worksheet image insertion: "
                          "unsupported image format for: %s.",

test/functional/helper_functions.py

@@ -151,7 +151,7 @@ def _compare_xlsx_files(got_file, exp_file, ignore_files, ignore_elements):
 
         # Compare binary files with string comparison based on extension.
         extension = os.path.splitext(filename)[1]
-        if extension in ('.png', '.jpeg', '.bmp', '.bin'):
+        if extension in ('.png', '.jpeg', '.gif','.bmp', '.bin'):
             if got_xml_str != exp_xml_str:
                 return 'got: %s' % filename, 'exp: %s' % filename
             continue

test/functional/src/test_image56.c

@@ -0,0 +1,20 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = workbook_new("test_image56.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+
+    worksheet_insert_image(worksheet, CELL("E9"), "images/red.gif");
+
+    return workbook_close(workbook);
+}

test/functional/src/test_image57.c

@@ -0,0 +1,20 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = workbook_new("test_image57.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+
+    worksheet_insert_image(worksheet, CELL("E9"), "images/logo.gif");
+
+    return workbook_close(workbook);
+}

test/functional/test_image.py

@@ -156,6 +156,12 @@ class TestCompareXLSXFiles(base_test_class.XLSXBaseTest):
     def test_image55(self):
         self.run_exe_test('test_image55')
 
+    def test_image56(self):
+        self.run_exe_test('test_image56')
+
+    def test_image57(self):
+        self.run_exe_test('test_image57')
+
     # Test in-memory image handling.
     def test_image81(self):
         self.run_exe_test('test_image81', 'image01.xlsx')