add auto fit columns function

col.go

@@ -17,6 +17,7 @@ import (
  "math"
  "strconv"
  "strings"
+ "unicode/utf8"
 
  "github.com/mohae/deepcopy"
 )
@@ -479,9 +480,15 @@ func (f *File) SetColWidth(sheet, startCol, endCol string, width float64) error
  if err != nil {
  return err
  }
+
+ return f.setColWidth(sheet, min, max, width)
+}
+
+func (f *File) setColWidth(sheet string, min, max int, width float64) error {
  if width > MaxColumnWidth {
  return ErrColumnWidth
  }
+
  ws, err := f.workSheetReader(sheet)
  if err != nil {
  return err
@@ -512,6 +519,81 @@ func (f *File) SetColWidth(sheet, startCol, endCol string, width float64) error
  return err
 }
 
+// AutoFitColWidth provides a function to autofit columns according to
+// their text content with default font size and font.
+// Note: this only works on the column with cells which not contains
+// formula cell and style with a number format.
+//
+// For example set column of column H on Sheet1:
+//
+// err = f.AutoFitColWidth("Sheet1", "H")
+//
+// Set style of columns C:F on Sheet1:
+//
+// err = f.AutoFitColWidth("Sheet1", "C:F")
+func (f *File) AutoFitColWidth(sheetName, columns string) error {
+ startColIdx, endColIdx, err := f.parseColRange(columns)
+ if err != nil {
+ return err
+ }
+
+ cols, err := f.Cols(sheetName)
+ if err != nil {
+ return err
+ }
+
+ colIdx := 1
+ for cols.Next() {
+ if colIdx >= startColIdx && colIdx <= endColIdx {
+ rowCells, _ := cols.Rows()
+ var max int
+ for i := range rowCells {
+ rowCell := rowCells[i]
+
+ // Single Byte Character Set(SBCS) is 1 holds
+ // Multi-Byte Character System(MBCS) is 2 holds
+ var cellLenSBCS, cellLenMBCS int
+ for ii := range rowCell {
+ if rowCell[ii] < 0x80 {
+ cellLenSBCS++
+ }
+ }
+
+ runeLen := utf8.RuneCountInString(rowCell)
+ cellLenMBCS = runeLen - cellLenSBCS
+
+ cellWidth := cellLenSBCS + cellLenMBCS*2
+ if cellWidth > max {
+ max = cellWidth
+ }
+ }
+
+ // The ratio of 1.123 is the best approximation I tried my best to
+ // find.
+ actualMax := float64(max) * 1.123
+
+ if actualMax < defaultColWidth {
+ actualMax = defaultColWidth
+ } else if actualMax >= MaxColumnWidth {
+ actualMax = MaxColumnWidth
+ }
+
+ if err := f.setColWidth(sheetName, colIdx, colIdx, actualMax); err != nil {
+ return err
+ }
+ }
+
+ // fast go away.
+ if colIdx == endColIdx {
+ break
+ }
+
+ colIdx++
+ }
+
+ return nil
+}
+
 // flatCols provides a method for the column's operation functions to flatten
 // and check the worksheet columns.
 func flatCols(col xlsxCol, cols []xlsxCol, replacer func(fc, c xlsxCol) xlsxCol) []xlsxCol {

col_test.go

@@ -2,7 +2,9 @@ package excelize
 
 import (
  "path/filepath"
+ "strings"
  "testing"
+ "unicode/utf8"
 
  "github.com/stretchr/testify/assert"
  "github.com/stretchr/testify/require"
@@ -360,6 +362,49 @@ func TestColWidth(t *testing.T) {
  convertRowHeightToPixels(0)
 }
 
+func TestAutoFitColWidth(t *testing.T) {
+ getCellLen := func(s string) int {
+ var cellLenSBCS, cellLenMBCS int
+ for i := range s {
+ if s[i] < 0x80 {
+ cellLenSBCS++
+ }
+ }
+
+ runeLen := utf8.RuneCountInString(s)
+ cellLenMBCS = runeLen - cellLenSBCS
+
+ return cellLenSBCS + cellLenMBCS*2
+ }
+
+ for _, c := range []string{"", "A", "a", "a你好", "你好", "あなた"} {
+ f := NewFile()
+ for i := 1; i <= 10; i++ {
+ colN, err := ColumnNumberToName(i)
+ assert.NoError(t, err)
+
+ v := strings.Repeat(c, i)
+ assert.NoError(t, f.SetCellValue("Sheet1", colN+"1", v))
+
+ assert.NoError(t, f.AutoFitColWidth("Sheet1", colN))
+
+ got, err := f.GetColWidth("Sheet1", colN)
+ assert.CallerInfo()
+ assert.NoError(t, err)
+
+ actualLen := float64(getCellLen(v)) * 1.123
+ if actualLen < defaultColWidth {
+ assert.Equal(t, defaultColWidth, got)
+ } else if actualLen >= MaxColumnWidth {
+ assert.Equal(t, float64(MaxColumnWidth), got)
+ } else {
+ assert.Equal(t, actualLen, got)
+ }
+ }
+ assert.NoError(t, f.SaveAs(filepath.Join("test", "TestAutoColWidth.xlsx")))
+ }
+}
+
 func TestGetColStyle(t *testing.T) {
  f := NewFile()
  styleID, err := f.GetColStyle("Sheet1", "A")