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GMImage.FontTypeMetrics

Queries space needed for text.

Component Version macOS Windows Linux Server iOS SDK
GraphicsMagick 7.3 ✅ Yes ✅ Yes ✅ Yes ✅ Yes ✅ Yes
MBS( "GMImage.FontTypeMetrics"; ImageRef; text )   More

Parameters

Parameter Description Example
ImageRef The image reference number. 1
text Some text "Hello World"

Result

Returns list or error.

Description

Queries space needed for text.
Obtain font metrics for text string given current font, point size, and density settings.
Returns list with following values:
  • text width in pixel
  • text height in pixel
  • Ascent, the distance in pixels from the text baseline to the highest/upper grid coordinate used to place an outline point.
  • Descent, the distance in pixels from the baseline to the lowest grid coordinate used to place an outline point. Always a negative value.
  • Maximum horizontal advance in pixels.
  • Font size

To extract values, please pass through Math.TextToNumber or similar functions which always uses dot as decimal separator.
See also Font.CalculateTextWidth function.

Examples

Draw some text on a picture:

# open a picture
Set Variable [ $ref ; Value: MBS("GMImage.NewFromContainer"; Annotate Image::InputImage) ]
# set font size
Set Variable [ $r ; Value: MBS("GMImage.SetFontPointsize"; $ref; 20) ]
# set the font
Set Variable [ $r ; Value: MBS("GMImage.SetFont"; $ref; "@/System/Library/Fonts/LucidaGrande.ttc") ]
# set the fill color
Set Variable [ $r ; Value: MBS("GMImage.SetFillColor"; $ref; "RGB 0 0 0") ]
# Query size for this text:
Set Variable [ $r ; Value: MBS("GMImage.FontTypeMetrics"; $ref; Annotate Image::Text) ]
# draw the text:
Set Variable [ $r ; Value: MBS("GMImage.Annotate"; $ref; Annotate Image::Text; "100x200+10+40"; 1) ]
# write image
Set Field [ Annotate Image::OutputImage ; MBS( "GMImage.WriteToPNGContainer"; $ref ) ]
# free memory
Set Variable [ $Error ; Value: MBS("GMImage.Release";$ref) ]

Measure text:

MBS("GMImage.FontTypeMetrics"; $ref; Annotate Image::Text)

Example result:
"528.000000
47.000000
39.000000
-8.000000
66.000000
40.000000"

See also

Release notes

Example Databases

Blog Entries

This function checks for a license.

Created 20th June 2017, last changed 26th September 2021


GMImage.FontMap - GMImage.Format