Question

我刚开始使用libxlsxwriter来创建excel表。我的问题是我不知道如何集中图片以及如何以原始尺寸打印图片。只考虑该组只有3列，每列具有不同的大小，例如30,10,20。我需要知道找到偏移量和比例值需要什么计算。

lxw_image_options options = {.x_offset = 0,  .y_offset = 0,.x_scale  = 0.9, .y_scale  = 0.9};
worksheet_insert_image_opt(worksheet, row, 0, img_path, &options);

有了这个，我需要知道图片可以容纳多少行。然后我才能创建即将到来的集合而不重叠。

Answer 1

图片有多少行？

我想在这里展示我的发现以即兴表达结果。

int row=1;
lxw_image_options options = {.x_offset = 0,  .y_offset = 0};
worksheet_insert_image_opt(worksheet, row, 2,"logo.png", &options);
row+=(options.height/worksheet->default_row_pixels);

这里我使用变量 options.height 来计算图片保存的行数。 libxlsxwriter确实从图像文件读取高度（以像素为单位）。它仅对读取初始化变量使用struct变量选项，它永远不会在集合中写入任何内容。但我在工作表单的 worksheet_insert_image_opt 函数中添加了 user_options-＆gt; height = options-＆gt; height; 这一行。

 lxw_error worksheet_insert_image_opt(lxw_worksheet *self,
                           lxw_row_t row_num, lxw_col_t col_num,
                           const char *filename,
                           lxw_image_options *user_options)
{
    FILE *image_stream;
    char *short_name;
    lxw_image_options *options;

    if (!filename) {
        LXW_WARN("worksheet_insert_image()/_opt(): "
                 "filename must be specified.");
        return LXW_ERROR_NULL_PARAMETER_IGNORED;
    }

    /* Check that the image file exists and can be opened. */
    image_stream = fopen(filename, "rb");
    if (!image_stream) {
        LXW_WARN_FORMAT1("worksheet_insert_image()/_opt(): "
                         "file doesn't exist or can't be opened: %s.",
                         filename);
        return LXW_ERROR_PARAMETER_VALIDATION;
    }

    /* Get the filename from the full path to add to the Drawing object. */
    short_name = lxw_basename(filename);
    if (!short_name) {
        LXW_WARN_FORMAT1("worksheet_insert_image()/_opt(): "
                         "couldn't get basename for file: %s.", filename);
        fclose(image_stream);
        return LXW_ERROR_PARAMETER_VALIDATION;
    }

    /* Create a new object to hold the image options. */
    options = calloc(1, sizeof(lxw_image_options));
    if (!options) {
        fclose(image_stream);
        return LXW_ERROR_MEMORY_MALLOC_FAILED;
    }

    if (user_options) {
        memcpy(options, user_options, sizeof(lxw_image_options));
        options->url = lxw_strdup(user_options->url);
        options->tip = lxw_strdup(user_options->tip);
    }

    /* Copy other options or set defaults. */
    options->filename = lxw_strdup(filename);
    options->short_name = lxw_strdup(short_name);
    options->stream = image_stream;
    options->row = row_num;
    options->col = col_num;

    if (!options->x_scale)
        options->x_scale = 1;

    if (!options->y_scale)
        options->y_scale = 1;

    if (_get_image_properties(options) == LXW_NO_ERROR) {
        user_options->height=options->height;
        STAILQ_INSERT_TAIL(self->image_data, options, list_pointers);
        return LXW_NO_ERROR;
    }
    else {
        free(options);
        return LXW_ERROR_IMAGE_DIMENSIONS;
    }
}

这是我如何计算行数。如果有更好的方法，请告诉我。

Answer 2

如何以原始尺寸打印图片

libxlsxwriter根据图像中的宽度，高度和DPI信息，将图像以原始大小插入xlsx文件。它应该以与通过用户界面在Excel中执行的方式完全相同的方式插入图像。

但是，OpenOffice或LibreOffice中的图像可能显示的大小不正确。这不是一个libxlsxwriter问题：Excel也会发生同样的事情。

要在精确位置插入图像，您需要知道图像的尺寸（以像素为单位）以及DPI，因为Excel会根据它的默认DPI（通常为96）进行缩放。以下是插入两个图像的示例一排：

/*
 * An example of inserting images with the libxlsxwriter library.
 */
#include "xlsxwriter.h"

int main() {

    /* Create a new workbook and add a worksheet. */
    lxw_workbook  *workbook   = workbook_new("demo.xlsx");
    lxw_worksheet *worksheet  = workbook_add_worksheet(workbook, NULL);
    lxw_image_options options = {.x_offset = 0, .y_offset = 0,
                                 .x_scale  = 1, .y_scale = 1};

    double default_dpi   = 96.0;
    double image_dpi     = 90.0;
    int32_t image_height = 138;
    int32_t image_offset = (int32_t)(image_height * default_dpi/image_dpi);

    /* Insert the first image. */
    worksheet_insert_image(worksheet, 1, 2, "logo.png");

    /* Insert the second image relative to the first. */
    options.y_offset += image_offset;
    worksheet_insert_image_opt(worksheet, 1, 2, "logo.png", &options);    

    workbook_close(workbook);

    return 0;
}

输出：

如何使用libxlsxwriter在Excel中以原始大小打印图像？

2 个答案: