Image (Type of variable)

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Properties specific to the description of Image variables
Accessing the pixels
Managing the Alpha channel
Image variable and Image control
Image variable and debugger
Creating an image with a specific size
Available EXIF tags
Functions that use Image variables
Functions (prefix syntax) that handle Image variables

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Image (Type of variable)

In french: Image

The Image type is used to define the advanced characteristics of an image. The characteristics of this image can be defined and changed using different WLanguage properties.

Remark: For more details on the declaration of this type of variable and the use of WLanguage properties, see Declaring a variable.

Example

MyImage is Image
MyImage.Width = 500
MyImage.Height = 100
// Load from a file
MyImage = dLoadImage("image.png")
// Equivalent syntaxes
// MyImage = "image.png"
// MyImage..Image = "image.png"

// Draw in the image
dStartDrawing(MyImage)

// Write a text
dFont("Arial", 12, iNormal, 0)
dText(4, 0, "I am writing my text in an Image control!")

// Resize
dResize(MyImage, 100, 100)

// End of drawing
dEndDrawing(MyImage)

// Assign to an Image control
IMG_ImageControl = MyImage

Remarks

Properties specific to the description of Image variables

The following properties can be used to handle an Image variable:

Property name	Type used	Effect

BitPerPixel	Integer	Number of bits per pixel. This property is read-only.
DrawingScale	Real	Scale that will be used for the drawing functions (dXXX functions): the coordinates used by these functions will be multiplied by this value. This property is not available.
EXIF[Exif tag]	Associative array	Allows you to get and change the content of the specified Exif tag. Modified Exif tags can be saved using dSaveImageJPEG with the imgSaveTag constant. The Empty property is used to determine if the content of the Exif tag is empty. For example: MyImage is Image ... IF NOT MyImage.EXIF[320]..Empty THEN IsTagValue = MyImage.EXIF[320] END The available Exif tags are listed in the Remarks. This property is not available.
FillColor	Color variable	Fill color of the image. This color is used: when the image is resized (Height and Width properties). when turning the image around (dRotation).
Height	Integer	Image height in pixels. If this property is modified, the image is not deformed: additional pixels are added. The color of these pixels is defined with the FillColor property.
Image	All types	Used to load an image from a buffer, a file or a memo. This property is equivalent to dLoadImage. Remarks: In read mode, this property returns a buffer containing the image in PNG format. The images in SVG or PDF format are not supported. To manage these formats, you must use dLoadImage. The animated images are not supported. A single page of multi-page images (TIF, ICO) can be loaded. Only the first page is loaded. You have the ability to draw a chart in an Image variable via grDestinationImage. The ICO format is not supported by iOS.
Pixel[x,y]	Array of Color	Used to handle the pixels of the image.
Valid	Boolean	Returns the validity of the image: True if the image is valid: it was successfully loaded or created. False otherwise. This property is read-only.
Width	Integer	Image width in pixels. If this property is modified, the image is not deformed: additional pixels are added. The color of these pixels is defined with the FillColor property.
WithAlpha	Boolean	Used to find out whether the image contains an alpha channel: True if the image contains an alpha channel, False otherwise. This property is read-only.

Accessing the pixels

To access the pixels of the image, you have the ability to use the following syntax:

<Name of Image Variable>[<Horizontal coordinate>, <Vertical coordinate>]

The origin of the coordinates is (0,0).

For example:

// Modify the pixel at coordinates 220,300
MyImage[220,300] = LightYellow

You also have the ability to use the Color properties. For example:

MyImage[220,300].Lightness = MyImage[220,300].Lightness + 10

Managing the Alpha channel

An image contains an Alpha channel in the following cases:

if it was created by default with an alpha channel, specified with the FillColor property.
if it was loaded from an image format containing an alpha channel (PNG format for example).

You can also handle the Alpha channel of the image by handling its pixels.

Image variable and Image control

You can:

assign an Image variable to an Image control.
assign an Image control to an Image variable.

These operations are available for the Image controls found in the window editor, page editor and report editor.

Image variable and debugger

The content of an Image variable can be viewed in the debugger.

Creating an image with a specific size

To create an image with a specific size, all you have to do is use Width and Height.

For example:

MyImage is Image
MyImage.Width = 10
MyImage.Height = 10

The unit used is the pixel.

The following code creates an image of 0 x 0.

MyImage is Image

Available EXIF tags

The table below lists the Exif tag values and the corresponding constants:

Tag	WLanguage constant	Value

37510	imgComment	Character string Comments about the image
37122	imgCompression	Real Compression of the image in bits/pixel
33432	imgCopyright	Character string Copyright of the image
306	imgDate	Date Date and time of the image in YYYY:MM:DD HH:MM:SS format
270	imgDescription	Character string Image description
37382	imgSubjectDistance	Real Distance from the subject in meters
37380	imgExposureBias	Real Exposure bias in APEX
37385	imgFlash	Integer Status of the flash during the shot: 0: Flash off. 1: Flash on. 5: Flash on and light not detected. 7: Flash on and light detected.
928	imgHeight	Integer Height of image in pixels
672	imgWidth	Integer Width of image in pixels
305	imgRecordingSoftware	Character string Name of the software that was used to record the image.
37386	imgFocalLength	Real Focal length in millimeters
37379	imgBrightness	Real Brightness of the image in APEX
271	imgDeviceMark	Character string Mark of the camera that took the photo
272	imgDeviceModel	Character string Model of camera that took the photo
37383	imgMeteringMode	Integer Metering mode: 0: unknown. 1: average. 2: average centered. 3: point. 4: multidot. 5: pattern. 6: partial. 7 to 254: reserved. 255: other.
37500	imgManufacturerNote	Character string Name of the camera manufacturer
274	imgOrientation	Integer Orientation of the image: This information indicates the location of the point (0,0) in the image. To display the image in the correct direction based on this information, use the following values: 1: the point (0,0) is at the top left, there is nothing to do. 2: the point (0,0) is at the top right, the image must be flipped horizontally. 3: the point (0,0) is at the bottom right, the image must be flipped horizontally and vertically. 4: the point (0,0) is at the bottom left, the image must be flipped horizontally. 5: the point (0,0) is at the top left, the image must be flipped horizontally and rotated 90°. 6: the point (0,0) is at the top right, the image must be rotated 90°. 7: the point (0,0) is at the bottom left, the image must be flipped vertically and rotated 90°. 8: the point (0,0) is at the bottom right, the image must be rotated -90°.
37378	imgAperture	Real Aperture in APEX
33437	imgFAperture	Real Focal
37381	imgMaxAperture	Real Maximum aperture in APEX
34850	imgExposureProgram	Integer Exposure mode used during the shot: 0: undefined. 1: manual. 2: normal. 3: priority to aperture. 4: priority to speed. 5: creation. 6: action. 7: close-up portrait without background. 8: landscape. 9 to 255: others.
282	imgXResolution	Real Horizontal resolution of the image
283	imgYResolution	Real Vertical resolution of the image
37384	imgLightSource	Integer Light source for the image: 0: unknown. 1: daylight. 2: fluorescent. 3: tungsten. 17: standard light A. 18: standard light B. 19: standard light C. 20: D55. 21: D65. 22: D75. 23 to 254: reserved. 255: other.
33434	imgExposureTime	Real Exposure time
296	imgResolutionUnit	Integer Unit for the horizontal and vertical resolution of the image: 2: inches. 3: centimeters.
36864	imgEXIFVersion	Character string Version of Exif information
65536	imgThumbnail	Binary string Thumbnail corresponding to the image
37377	imgShutterSpeed	Real Shutter speed in APEX

Other tags are also available. These unlisted tags are specific to some types of cameras or correspond to custom tags.

Functions that use Image variables


AlbumSave	Saves an image, a photo or a video in the photo album of the mobile device.
BCToImage	Generates the image of a bar code.
dArc	Draws an arc of circle or an arc of ellipse: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dBorder	Draws the borders.
dCircle	Draws a circle or an ellipse: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dChangeMode	Changes the drawing mode used by the drawing functions (dLine, dRectangle, ....).
dLoadImage	Loads an image in an Image variable from a memo, a file or a binary buffer.
dCopy	Copies an image to another image.
dCopyBlt	Copies an image: from an Image control to another Image control. from an Image variable to another Image variable.
dCopyScreenImage	Copies the screen content to an Image variable or to an Image control.
dCopyWindowImage	Copies the image from a WINDEV window to an Image variable or to an Image control.
dChord	Draws the chord of a circle (intersection between an ellipse and a straight line): in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dDominantImageColor	Returns the dominant (i.e. most frequent) color of an image in an Image variable or in an Image control.
dStartDrawing	Indicates that the drawing functions that will be used are intended for: the specified Image control, the specified Image variable, the specified Image variable, the specified WDPic variable (on the background layer), the specified picLayer variable.
dCrop	Returns the cropped part of an image. This image is found in an Image variable.
dEndDrawing	Deletes all the drawings made since the last call to dStartDrawing.
dBlur	Blurs the entire given area: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dBackground	Declares the default background color for the rectangles, circles, etc.:: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dAlphaBlend	Blends two images together. This allows you to create fade-in effects between 2 images.
dHalo	Adds a halo effect on an image found in an Image variable].
DiagramToImage	Exports a diagram to a variable of type Image.
dEncrustColor	Encrusts a color in an image found in an Image variable].
dInvertColor	Inverts the colors: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dLine	Draws a line: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dModifyLightness	Changes the lightness of an image found: in an Image control, in an Image variable.
dModifyOpacity	Modifies the opacity of an image (which means the alpha channel of the image).
dModifySaturation	Modifies the saturation of an image found: in an Image control, in an Image variable.
dModifyHue	Changes the hue of an image: in an Image control, in an Image variable.
dModifyHSL	Modifies the hue, the saturation and the lightness of an image found: in an Image control, in an Image variable.
DocAdd	Adds: at the end of a Word Processing document: an element, a document, a paragraph, a text, an image or a fragment. at the end of a fragment: an element, a text or an image.
DocInsert	Inserts an object into a Word Processing document or replaces the content of the current fragment. The objects that can be used are: an element, a document, a paragraph, a text, an image, a fragment.
DocToImage	Exports a page found in a Word Processing document in image format.
dShadow	Adds a shadow effect on an image found in an Image variable].
dPixelColor	Identifies the color of a pixel: in an Image control, in an Image variable. in a picLayer variable. in a WDPic variable.
dPixelOpacity	Identifies the opacity of a pixel in an image that has an Alpha channel. This image can be: an Image control, an Image variable, a WDPic variable (on the background layer), a picLayer variable.
dPoint	Draws a point: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dFont	Declares the font that will be used by dText: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dPolygon	Draws a polygon: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dPolyline	Draws a line composed of multiple segments.
dSlice	Draws a circle section or an ellipse section: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dRectangle	Draws a rectangle: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dRoundedRectangle	Draws a rounded rectangle: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dRectangleGradient	Draws a rectangle: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dResize	Resizes an image: in an Image control, in an Image variable. in a picLayer variable].
dFill	Colors an area: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dRotation	Performs a rotation: of an Image control, of an Image variable, of a picLayer variable.
dSaveImageBMP	Saves an image: in a file in BMP format. in memory.
dSaveImageGIF	Saves an image: in a file in GIF format. in memory.
dSaveImageJPEG	Saves an image: in a JPEG file. in memory.
dSaveImagePNG	Saves an image: in a PNG file. in memory.
dPen	Declares the default color and style for the lines, rectangles, circles, ... found: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dHorizontalSymmetry	Flips an image with respect to a horizontal axis (symmetry with respect to a horizontal axis).
dVerticalSymmetry	Flips an image with respect to a vertical axis (symmetry with respect to a vertical axis).
dText	Draws a text: in an Image control, in an Image variable, in a WDPic variable (on the background layer), in a picLayer variable.
dTextRTF	Draws RTF text: in an Image control, in an Image variable.
dTransferToImage	Creates an image from a buffer of pixels encoded in a specific format. This function is an advanced function. This function is mainly used to handle the images returned by external APIs via Image variables.
grDestinationImage	Defines an Image variable as destination of a chart.
grSaveImage	Saves the image of a chart in an Image variable.
iImageHeight	Calculates the height of the image to print (in millimeters).
iPrintImage	Sends the image file to print to the print buffer.
iImageWidth	Calculates the width of the image to print (in millimeters).
PDFExtractPage	Returns an Image type variable containing a page from a PDF file.
Clipboard	Retrieves the text or image found in the system clipboard.
ToClipboard	Writes text or image information into the system clipboard.

Functions (prefix syntax) that handle Image variables


<Image variable>.DrawArc	Draws a circle arc or an ellipse arc in an Image variable.
<Image variable>.DrawBorder	Draws the borders in an Image variable.
<Image variable>.DrawCircle	Draws a circle or an ellipse in an Image variable.
<Image variable>.ChangeMode	Changes the drawing mode used by the drawing functions (dLine, dRectangle, ....).
<Image variable>.Copy	Copies an image to another image.
<Image variable>.DrawChord	Draws the chord of a circle (intersection between an ellipse and a straight line) in an Image variable.
<Image variable>.DominantImageColor	Returns the dominant color (i.e. most frequent color) of an image found in an Image variable.
<Image variable>.StartDrawing	Indicates that the drawing functions that will be used are intended for an Image variable.
<Image variable>.Crop	Returns the cropped part of an image. This image is found in an Image variable.
<Image variable>.Background	Declares the default background color for the rectangles and circles, ... used in an Image variable.
<Image variable>.DrawHalo	Adds a halo effect on an image found in an Image variable].
<Image variable>.EncrustColor	Encrusts a color in an image found in an Image variable].
<Image variable>.InvertColor	Inverts the colors in an Image variable.
<Image variable>.DrawLine	Draws a line in an Image variable.
<Image variable>.ModifyLightness	Modifies the lightness of an image in an Image variable.
<Image variable>.ModifyOpacity	Modifies the opacity of an image (which means the alpha channel of the image).
<Image variable>.ModifySaturation	Modifies the saturation of an image in an Image variable.
<Image variable>.ModifyHue	Changes the hue of an image in an Image variable.
<Image variable>.ModifyHSL	Modifies the hue, saturation and lightness of an image in an Image variable.
<Image variable>.DrawShadow	Adds a shadow effect on an image found in an Image variable].
<Image variable>.PixelColor	Identifies the color of a pixel contained in an Image variable.
<Image variable>.PixelOpacity	Identifies the opacity of a pixel in an image (in an Image variable) with an Alpha channel.
<Image variable>.DrawPoint	Draws a point in an Image variable.
<Image variable>.Font	Declares the font that will be used by dText in an Image variable.
<Image variable>.DrawPolygon	Draws a polygon in an Image variable.
<Image variable>.DrawPolyline	Draws a line composed of multiple segments in an Image variable.
<Image variable>.DrawSlice	Draws a section of a circle or an ellipse in an Image variable.
<Image variable>.DrawRoundedRectangle	Draws a rounded rectangle in an Image variable.
<Image variable>.DrawRectangleGradient	Draws a rectangle in an Image variable.
<Image variable>.DrawRectangle	Draws a rectangle in an Image variable.
<Image variable>.Resize	Resizes an image in an Image variable.
<Image variable>.Fill	Colors an area in an Image variable.
<Image variable>.Rotation	Rotates an image in an Image variable.
<Image variable>.SaveBMP	Saves an image contained in an Image variable: in a file in BMP format. in memory.
<Image variable>.SaveGIF	Saves an image found in an Image variable: in a file in GIF format. in memory.
<Image variable>.SaveJPEG	Saves an image found in an Image variable: in a JPEG file. in memory.
<Image variable>.SavePNG	Saves an image found in an Image variable: in a PNG file. in memory.
<Image variable>.Pen	Declares the default color and style for the lines, rectangles, circles, ... in an Image variable.
<Image variable>.HorizontalSymmetry	Flips an image contained in an Image variable with respect to a horizontal axis (symmetry with respect to a horizontal axis).
<Image variable>.VerticalSymmetry	Flips an image contained in an Image variable with respect to a vertical axis (symmetry with respect to a vertical axis).
<Image variable>.DrawTextRTF	Draws an RTF text in an Image variable.
<Image variable>.DrawText	Draws a text in an Image variable.