picture — `u_pbt_picture` #

Image display: every common format, framing modes, alignment, automatic graying and a counter badge.

▶ See it live — Demo application, Picture tile: the preview, the code behind it and this page, side by side.

At a glance #

Userobject	`u_pbt_picture`
Item class	— (component without items)
Used for	Replacing a PowerBuilder `picture`: modern formats (SVG, WebP, animated GIF), controlled framing, clickable image, automatic graying
Opt-in options	`ib_track_mouse`

Quick start #

// window open event
uo_image.is_source  = "img\logo.png"
uo_image.is_stretch = uo_image.STRETCH_UNIFORM   // fits without distorting
uo_image.is_align   = uo_image.ALIGN_CENTER
uo_image.is_tooltip = "Company logo"

Where the image comes from: `is_source` #

is_source accepts four forms, all interchangeable:

Form	Example	Use
Local file	`img\logo.png`	png, jpg, bmp, gif, ico, svg, webp
Web address	`https://…/logo.png`	Image loaded from a server (`http` or `https`)
Embedded data	`data:image/png;base64,…`	Image already in memory, with no intermediate file
DLL resource	`img\packimages.dll:SAMPLE`	Image packaged in a resource DLL

An anim: prefix can be placed in front of a GIF to explicitly flag an animation (GIFs animate anyway).

When the same name exists under several resource types in a DLL, state the type: img\packimages.dll:PNG/SAMPLE, SVG/SAMPLE, ICON/APP, RCDATA/BLOB. See Images and icons for the mono: and tint: prefixes, which recolor a glyph according to the theme.

How it is framed: `is_stretch` #

Constant	Effect
`STRETCH_UNIFORM`	Default. The image is scaled without distortion and stays fully visible; margins may appear
`STRETCH_UNIFORMTOFILL`	Scaled without distortion, but the frame is filled completely; anything overflowing is cropped
`STRETCH_FILL`	The image is stretched to fit the frame exactly — it may be distorted
`STRETCH_NONE`	Original size, no scaling

is_align decides the horizontal position of the image when it is smaller than the control: ALIGN_CENTER (default), ALIGN_START, ALIGN_END. The vertical axis has its own property, is_valign.

Constants #

Constant	Value	For
`STRETCH_NONE` · `STRETCH_FILL` · `STRETCH_UNIFORM` · `STRETCH_UNIFORMTOFILL`	`"none"` `"fill"` `"uniform"` `"uniformtofill"`	`is_stretch`
`ALIGN_CENTER` · `ALIGN_START` · `ALIGN_END`	`"center"` `"start"` `"end"`	`is_align`
`VALIGN_TOP` · `VALIGN_CENTER` · `VALIGN_BOTTOM`	`"top"` `"center"` `"bottom"`	`is_valign`
`is_valign`	string	`VALIGN_CENTER`	Vertical placement when the image is smaller than the control: `VALIGN_TOP`, `VALIGN_CENTER`, `VALIGN_BOTTOM`. The two axes are independent — `is_align` gives the column, this one the row — which is what makes a corner reachable
`ROTATION_NONE` · `ROTATION_90` · `ROTATION_180` · `ROTATION_270`	`0` `90` `180` `270`	`ii_rotation`

ALIGN_START and ALIGN_END are logical: they follow the writing direction (Language and RTL). The physical values left and right are still accepted as aliases.

Properties #

Property	Type	Default	Purpose
`is_source`	string	`""`	The image to display (see the four forms above)
`is_stretch`	string	`"uniform"`	Framing mode: `STRETCH_NONE`, `STRETCH_FILL`, `STRETCH_UNIFORM`, `STRETCH_UNIFORMTOFILL`
`is_align`	string	`"center"`	Horizontal placement when the image is smaller than the control: `ALIGN_CENTER`, `ALIGN_START`, `ALIGN_END`. The vertical axis is `is_valign`
`ib_enabled`	boolean	`true`	When `false`, the image is displayed in grayscale
`ii_badge`	integer	`0`	Counter badge in the upper-right corner (`0` = none)
`il_badge_color`	long	`0`	Badge background, as a PowerBuilder RGB value (`0` = the color that comes from the theme). The text color is picked automatically so that the counter stays legible
`ii_badge_size`	integer	`0`	Badge height in pixels (`0` = the size that comes from the theme). The font size follows on its own: the counter stays centered whatever the size
`ib_track_mouse`	boolean	`false`	Opt-in: enables `ue_mouse_enter` / `ue_mouse_leave`
`is_placeholder`	string	`""`	Stand-in image, shown while `is_source` is empty (an « add a photo » frame, a silhouette). Displayed dimmed: a stand-in is not the content, and it is never announced as a loaded image. Accepts the `mono:` prefix, which recolours a monochrome glyph with the theme
`is_error_source`	string	`""`	Fallback image when the source fails to load. Leave it empty and the component shows its own error glyph — never an empty box, which tells the user nothing while `ue_error` only travels to your code. Accepts the `mono:` prefix
`ii_rotation`	integer	`0`	Quarter turns, for the scans and photos that arrive lying down: `ROTATION_NONE`, `ROTATION_90`, `ROTATION_180`, `ROTATION_270` (anything else reads as 0). A quarter turn swaps the fitting axes as well, so the picture keeps its proportions instead of being squashed
`ib_mirror`	boolean	`false`	Horizontal mirror, applied on top of the rotation
`ib_zoomable`	boolean	`false`	Opt-in: the user may come closer (wheel), move around (drag) and go back to the fitted view (double click). For a plan, a scan or a photo — where four fixed fitting modes are not enough
`id_zoom`	double	`1.0`	Zoom factor: `1.0` means the whole picture fits, up to `8.0`. Reading it back gives the current factor, wheel included (`ue_zoom_changed` tells you at every step). Needs `ib_zoomable`
`ib_allow_drop`	boolean	`false`	Opt-in: accepts files dropped from the Windows Explorer. The frame shows it is armed, and the full paths arrive through `ue_drop_files` — loading them into `is_source` is up to your application
`ib_auto_height`	boolean	`false`	Opt-in: the userobject takes the height that keeps the image's proportions at its current width. For a picture that height is deducible: no need to compute it yourself from the dimensions reported by `ue_loaded`
`is_theme_style`	string	`fluent`	Visual style of the component (`THEME_STYLE_*` constants)
`is_theme_mode`	string	`light`	Light or dark variant (`THEME_MODE_*` constants)
`il_theme_accent`	long	`-1`	Accent color of this component (`-1` = the theme accent)
`is_tooltip`	string	`""`	Simple tooltip shown when hovering the component
`is_super_tooltip_title`	string	`""`	Title of the rich tooltip (takes precedence over `is_tooltip`)
`is_super_tooltip_text`	string	`""`	Text of the rich tooltip (rich markup accepted)
`is_super_tooltip_image`	string	`""`	Image of the rich tooltip

Methods #

Method	Purpose
`of_reset ( )`	Resets every property to its default and removes the image
`of_set_redraw (boolean)`	Groups a burst of changes into a single render
`of_save_as_png (string)` · `of_save_as_jpg (string)`	Exports the rendering as an image

Events #

Event	Raised when
`ue_clicked ( )`	Left click on the image
`ue_loaded (long al_width, long al_height)`	The image has loaded; the arguments carry its original size in pixels
`ue_error (string as_message)`	The image could not be loaded (missing file, unreachable address, rejected format)
`ue_rclicked ( )`	Right click on the image
`ue_double_clicked ( )`	Double click on the image. The single clicks that precede it are raised too, in the same order. When `ib_zoomable` is on, the double click also brings the picture back to the fitted view: the event is raised either way, and what it means is up to you
`ue_zoom_changed (double ad_zoom)`	The zoom factor changed, whether from the wheel or from `id_zoom`. `1.0` means the whole picture fits again
`ue_auto_height (long al_height)`	The component settled on a new height; the userobject has already been resized when this fires. Needs `ib_auto_height`
`ue_drop_files (string as_files[])`	Files dropped from the Explorer: full paths, one entry per file. Needs `ib_allow_drop`
`ue_drag_enter ( )`	A file drag entered the component (`ib_allow_drop`)
`ue_drag_leave ( )`	The file drag left the component
`ue_mouse_enter ( )`	The mouse enters — requires `ib_track_mouse = true`
`ue_mouse_leave ( )`	The mouse leaves — requires `ib_track_mouse = true`
`ue_ready ( )`	The component has finished loading; everything sent beforehand has been replayed
`ue_runtime_missing ( )`	The WebView2 runtime is missing: the component stays empty
`ue_bg_color (long al_color)`	The component has computed its theme background color; the userobject has already adopted it (`backcolor`)

Examples #

Showing the photo on a record #

// ue_row_changed event of the datawindow : show the photo of the current customer
uo_photo.is_source  = "photos\" + ls_code_client + ".jpg"
uo_photo.is_stretch = uo_photo.STRETCH_UNIFORMTOFILL   // fills the frame, the overflow is cropped
uo_photo.is_align   = uo_photo.ALIGN_CENTER

// ue_error event of uo_photo : (string as_message)
uo_photo.is_source = "img\photo_absente.svg"     // fallback image

Handling ue_error is the right way to deal with a missing photo: there is no need to test whether the file exists before assigning it.

A clickable image, button-style #

uo_avatar.is_source    = "photos\utilisateur.png"
uo_avatar.is_tooltip   = "My account"

// ue_clicked event of uo_avatar
of_ouvrir_mon_compte()

Counter and graying #

// A notification badge on a mail icon
uo_messagerie.is_source = "img\packimages.dll:SVG/MAIL"
uo_messagerie.ii_badge  = ll_non_lus       // 0 makes the badge disappear

// Red beyond a threshold, theme color otherwise (0)
if ll_non_lus > 20 then
    uo_messagerie.il_badge_color = RGB(200, 30, 30)
else
    uo_messagerie.il_badge_color = 0
end if

// Feature unavailable : the image turns grayscale, with no second image to supply
uo_messagerie.ib_enabled = ib_droit_messagerie

Graying is computed automatically: you do not have to supply a second "disabled" image.

Finding out the real size of the image #

uo_apercu.is_source = ls_fichier_choisi

// ue_loaded event of uo_apercu : (long al_width, long al_height)
uo_statut.of_item("main").is_text = String(al_width) + " x " + String(al_height) + " px"

// An image smaller than the frame : do not enlarge it needlessly
if al_width < uo_apercu.width and al_height < uo_apercu.height then
    uo_apercu.is_stretch = uo_apercu.STRETCH_NONE
end if

uo_banniere.is_source  = "img\banniere.jpg"
uo_banniere.is_stretch = uo_banniere.STRETCH_UNIFORMTOFILL   // fills the whole strip, without distorting
uo_banniere.is_valign   = uo_banniere.VALIGN_TOP               // keeps the top of the image visible

Best practices #

STRETCH_UNIFORM is the safe mode: it never distorts. Save STRETCH_FILL for decorative backgrounds where distortion does not matter.
For a photo in a fixed frame (staff directory, thumbnail), STRETCH_UNIFORMTOFILL gives a consistent result, with no unsightly margins.
Bundle your icons in a resource DLL rather than shipping hundreds of files; the pack.dll:TYPE/NAME form removes any ambiguity.
For a monochrome glyph that has to follow the light and dark themes, use the mono: prefix (Images and icons).
Script ue_error on any image whose source depends on data: it is your only safety net when a file is missing.
Call of_reset() before reusing the component for a different kind of image: otherwise the previous framing mode, badge or grayed-out state stays in place.

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picture — u_pbt_picture #